Science & Tech IV

Delhi Law Academy


What is an Ecosystem?

•            The ecosystem is the structural and functional unit of ecology where the living organisms interact with each other and the surrounding environment. In other words, an ecosystem is a chain of interaction between organisms and their environment.

•            The term “Ecosystem” was first coined by A.G.Tansley, an English botanist, in 1935.

Types of Ecosystem

•            An ecosystem can be as small as an oasis in a desert, or as big as an ocean, spanning thousands of miles. There are two types of ecosystem:

  • Terrestrial Ecosystem
  • Aquatic Ecosystem

Terrestrial Ecosystems

•            Terrestrial ecosystems are exclusively land-based ecosystems. There are different types of terrestrial ecosystems distributed around various geological zones.

•            They are as follows:

  • Forest Ecosystems
  • Grassland Ecosystems
  • Tundra Ecosystems
  • Desert Ecosystem

Forest Ecosystem

•            A forest ecosystem consists of several plants, animals and microorganisms that live in coordination with the abiotic factors of the environment. Forests help in maintaining the temperature of the earth and are the major carbon sink.

Grassland Ecosystem

•            In a grassland ecosystem, the vegetation is dominated by grasses and herbs. Temperate grasslands, savanna grasslands are some of the examples of grassland ecosystems.

Tundra Ecosystem

•            Tundra ecosystems are devoid of trees and are found in cold climates or where rainfall is scarce. These are covered with snow for most of the year. The ecosystem in the Arctic or mountain tops is tundra type.

Desert Ecosystem

•            Deserts are found throughout the world. These are regions with very little rainfall. The days are hot and the nights are cold.

Aquatic Ecosystem

•            Aquatic ecosystems are ecosystems present in a body of water. These can be further divided into two types, namely:

  • Freshwater Ecosystem
  • Marine Ecosystem

Freshwater Ecosystem

•            The freshwater ecosystem is an aquatic ecosystem that includes lakes, ponds, rivers, streams and wetlands. These have no salt content in contrast with the marine ecosystem.

Marine Ecosystem

•            The marine ecosystem includes seas and oceans. These have a more substantial salt content and greater biodiversity in comparison to the freshwater ecosystem.

Structure of the Ecosystem

•            The structure of an ecosystem is characterised by the organisation of both biotic and abiotic components. This includes the distribution of energy in our environment. It also includes the climatic conditions prevailing in that particular environment.

The structure of an ecosystem can be split into two main components, namely:

  • Biotic Components
  • Abiotic Components

The biotic and abiotic components are interrelated in an ecosystem. It is an open system where the energy and components can flow throughout the boundaries.

Biotic Components

•            Biotic components refer to all life in an ecosystem.  Based on nutrition, biotic components can be categorised into autotrophs, heterotrophs and saprotrophs (or decomposers).

•            Producers include all autotrophs such as plants. They are called autotrophs as they can produce food through the process of photosynthesis. Consequently, all other organisms higher up on the food chain rely on producers for food.

•            Consumers or heterotrophs are organisms that depend on other organisms for food. Consumers are further classified into primary consumers, secondary consumers and tertiary consumers.

  • Primary consumers are always herbivores that they rely on producers for food.
  • Secondary consumers depend on primary consumers for energy. They can either be a carnivore or an omnivore.
  • Tertiary consumers are organisms that depend on secondary consumers for food.  Tertiary consumers can also be an omnivore.
  • Quaternary consumers are present in some food chains. These organisms prey on tertiary consumers for energy. Furthermore, they are usually at the top of a food chain as they have no natural predators.

•            Decomposers include saprophytes such as fungi and bacteria. They directly thrive on the dead and decaying organic matter.  Decomposers are essential for the ecosystem as they help in recycling nutrients to be reused by plants.

Abiotic Components

•            Abiotic components are the non-living component of an ecosystem.  It includes air, water, soil, minerals, sunlight, temperature, nutrients, wind, altitude, turbidity, etc.

Functions of Ecosystem

  • It regulates the essential ecological processes, supports life systems and renders stability.
  • It is also responsible for the cycling of nutrients between biotic and abiotic components.
  • It maintains a balance among the various trophic levels in the ecosystem.
  • It cycles the minerals through the biosphere.
  • The abiotic components help in the synthesis of organic components that involves the exchange of energy.

Important Ecological Concepts

1. Food Chain

•            The sun is the ultimate source of energy on earth. It provides the energy required for all plant life. The plants utilise this energy for the process of photosynthesis, which is used to synthesise their food.

•            During this biological process, light energy is converted into chemical energy and is passed on through successive levels. The flow of energy from a producer, to a consumer and eventually, to an apex predator or a detritivore is called the food chain.

•            Dead and decaying matter, along with organic debris, is broken down into its constituents by scavengers. The reducers then absorb these constituents. After gaining the energy, the reducers liberate molecules to the environment, which can be utilised again by the producers.

2. Ecological Pyramids

•            An ecological pyramid is the graphical representation of the number, energy, and biomass of the successive trophic levels of an ecosystem. Charles Elton was the first ecologist to describe the ecological pyramid and its principals in 1927.

•            The biomass, number, and energy of organisms ranging from the producer level to the consumer level are represented in the form of a pyramid; hence, it is known as the ecological pyramid.

•            The base of the ecological pyramid comprises the producers, followed by primary and secondary consumers. The tertiary consumers hold the apex. In some food chains, the quaternary consumers are at the very apex of the food chain.

•            The producers generally outnumber the primary consumers and similarly, the primary consumers outnumber the secondary consumers. And lastly, apex predators also follow the same trend as the other consumers; wherein, their numbers are considerably lower than the secondary consumers.

•            For example, Grasshoppers feed on crops such as cotton and wheat, which are plentiful. These grasshoppers are then preyed upon by common mice, which are comparatively less in number. The mice are preyed upon by snakes such as cobras. Snakes are ultimately preyed on by apex predators such as the brown snake eagle.

•            In essence:

Grasshopper →Mice→  Cobra → Brown Snake Eagle

3. Food Web

•            Food web is a network of interconnected food chains. It comprises all the food chains within a single ecosystem. It helps in understanding that plants lay the foundation of all the food chains. In a marine environment, phytoplankton forms the primary producer.



•            It is the atmospheric layer between the earth’s surface and an altitude of 8 km at the poles and 18 km at the equator.

•            The thickness is greater at the equator, because the heated air rises to greater heights.

•            The troposphere ends with the Tropopause.

•            The temperature in this layer, as one goes upwards, falls at the rate of 5°C per kilometer, and reaches -45°C at the poles and -80°C over the equator at Tropopause (greater fall in temperature above equator is because of the greater thickness of troposphere – 18 km).

•            The fall in temperature is called ‘lapse rate’. (more about this in future posts)

•            The troposphere is marked by temperature inversion, turbulence and eddies.

•            It is also meteorologically the most significant zone in the entire atmosphere (Almost all the weather phenomena like rainfall, fog and hailstorm etc. are confined to this layer).

•            It is also called the convective region, since all convection stops at Tropopause.

•            The troposphere is the theatre for weather because all cyclones, anticyclones, storms and precipitation occur here, as all water vapours and solid particles lie within this.

•            The troposphere is influenced by seasons and jet streams.


•            Top most layer of troposphere.

•            It acts as a boundary between troposphere and stratosphere.

•            This layer is marked by constant temperatures.


•            It lies beyond troposphere, up to an altitude of 50 km from the earth’s surface.

•            The temperature in this layer remains constant for some distance but then rises to reach a level of 0°C at 50 km altitude.

•            This rise is due to the presence of ozone (harmful ultraviolet radiation is absorbed by ozone).

•            This layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying aeroplanes. So aeroplanes fly in lower stratosphere, sometimes in upper troposphere where weather is calm.

•            Sometimes, cirrus clouds are present at lower levels in this layer.


•            It lies at an altitude between 30 km and 60 km from the earth’s surface and spans the stratosphere and lower mesosphere.

•            Because of the presence of ozone molecules, this layer reflects the harmful ultraviolet radiation.

•            The ozonosphere is also called chemosphere because, a lot of chemical activity goes on here.

•            The temperature rises at a rate of 5°C per kilometer through the ozonosphere.


•            This is an intermediate layer beyond the ozone layer and continues upto an altitude of 80 km from the earth’s surface.

•            The temperature gradually falls to -100°C at 80 km altitude.

•            Meteorites burn up in this layer on entering from the space.


•            In thermosphere temperature rises very rapidly with increasing height.

•            Ionosphere is a part of this layer. It extends between 80-400 km.

•            This layer helps in radio transmission. In fact, radio waves transmitted from the earth are reflected back to the earth by this layer.

•            Person would not feel warm because of the thermosphere’s extremely low pressure.

•            The International Space Station and satellites orbit in this layer. (Though temperature is high, the atmosphere is extremely rarified – gas molecules are spaced hundreds of kilometers apart. Hence a person or an object in this layer doesn’t feel the heat)

•            Auroras are observed in lower parts of this layer.


•            This layer is located between 80 km and 400 km and is an electrically charged layer.

•            This layer is characterized by ionization of atoms.

•            Because of the electric charge, radio waves transmitted from the earth are reflected back to the earth by this layer.

•            Temperature again starts increasing with height because of radiation from the sun.


•            This is the uppermost layer of the atmosphere extending beyond the ionosphere above a height of about 400 km.

•            The air is extremely rarefied and the temperature gradually increases through the layer.

•            Light gases like helium and hydrogen float into the space from here.

•            Temperature gradually increases through the layer. (As it is exposed to direct sunlight)

•            This layer merges into space.

Composition of Atmosphere

  • The atmosphere is a mixture of many gases. In addition, it contains huge numbers of solid and liquid particles, collectively called ‘aerosols’.
  • Some of the gases may be regarded as permanent atmospheric components which remain in fixed proportion to the total gas volume.
  • Other constituents vary in quantity from place to place and from time to time. If the suspended particles, water vapour and other variable gases were excluded from the atmosphere, then the dry air is very stable all over the earth up to an altitude of about 80 kilometres.
  • The proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.
  • Nitrogen and oxygen make up nearly 99% of the clean, dry air. The remaining gases are mostly inert and constitute about 1% of the atmosphere.
  • Besides these gases, large quantities of water vapour and dust particles are also present in the atmosphere. These solid and liquid particles are of great climatic significance.
  • Different constituents of the atmosphere, with their individual characteristics, are discussed below.


  • Oxygen, although constituting only 21% of total volume of atmosphere, is the most important component among gases.
  • All living organisms inhale oxygen. Besides, oxygen can combine with other elements to form important compounds, such as, oxides. Also, combustion is not possible without oxygen.


  • Nitrogen accounts for 78% of total atmospheric volume. It is a relatively inert gas, and is an important constituent of all organic compounds.
  • The main function of nitrogen is to control combustion by diluting oxygen. It also indirectly helps in oxidation of different kinds.

Carbon Dioxide

  • The third important gas is Carbon Dioxide which constitutes only about 03% of the dry air and is a product of combustion. Green plants, through photosynthesis, absorb carbon dioxide from the atmosphere and use it to manufacture food and keep other bio-physical processes going.
  • Being an efficient absorber of heat, carbon dioxide is considered to be of great climatic significance. Carbon dioxide is considered to be a very important factor in the heat energy budget.
  • With increased burning of fossil fuels – oil, coal and natural gas – the carbon dioxide percentage in the atmosphere has been increasing at an alarming rate.
  • More carbon dioxide in the atmosphere means more heat absorption. This could significantly raise the temperature at lower levels of the atmosphere thus inducing drastic climatic changes.

Ozone (03)

  • Ozone (03) is another important gas in the atmosphere, which is actually a type of oxygen molecule consisting of three, instead of two, atoms. It forms less than 0.00005% by volume of the atmosphere and is unevenly distributed.
  • It is between 20 km and 25 km altitude that the greatest concentrations of ozone are found. It is formed at higher altitudes and transported downwards.
  • Ozone plays a crucial role in blocking the harmful ultraviolet radiation from the sun.
  • Other gases found in almost negligible quantities in the atmosphere are neon, helium, hydrogen, xenon, krypton, methane etc.

Water Vapour

  • Water Vapour is one of the most variable gaseous substances present in atmosphere – constituting between 02% and 4% of the total volume (in cold dry and humid tropical climates respectively). 90% of moisture content in the atmosphere exists within 6 km of the surface of the earth. Like carbon dioxide, water vapour plays a significant role in the insulating action, of the atmosphere.
  • It absorbs not only the long-wave terrestrial radiation (infrared or heat emitted by earth during nights), but also a part of the incoming solar radiation.
  • Water vapour is the source of precipitation and clouds. On condensation, it releases latent heat of condensation —the ultimate driving force behind all storms.
  • The moisture – carrying capacity of air is directly proportional to the air temperature.

Solid Particles

  • The Solid Particles present in the atmosphere consist of sand particles (from weathered rocks and also derived from volcanic ash), pollen grains, small organisms, soot, ocean salts; the upper layers of the atmosphere may even have fragments of meteors which got burnt up in the atmosphere. These solid particles perform the function of absorbing, reflecting and scattering the radiation.
  • The solid particles are, consequently, responsible for the orange and red colours at sunset and sunrise and for the length of dawn (the first appearance of light in the sky before sunrise) and twilight (the soft glowing light from the sky when the sun is below the horizon, caused by the reflection of the sun’s rays by the atmosphere. Dusk: the darker stage of twilight.). The blue colour of the sky is also due to selective scattering by dust particles.
  • Some of the dust particles are hygroscopic (i.e. readily absorbing moisture from air) in character, and as such, act as nuclei of condensation. Thus, dust particles are an important contributory factor in the formation of clouds, fog and hailstones.



  • Nitrogen is a chief constituent of the bodies of living organisms as the Nitrogen atoms are found in all proteins and DNA
  • It is a common limiting nutrient in nature and agriculture.
  • It exists in the atmosphere as N2
  • Usually, nitrogen is usable only after it is fixed.
  • Nitrogen fixation is a process where bacteria convert N2 into ammonia, a form of nitrogen usable by plants.
  • Only a few types of organisms like and blue-green algae and certain species of soil bacteria are skilful of consuming nitrogen directly in its gaseous form.
  • When animals eat the plants, they obtain usable nitrogen compounds.
  • A limiting nutrient is a nutrient that’s in shortest supply and limits growth.
  • When fertilizers comprising phosphorous and nitrogen are transported in a runoff to rivers and lakes, they can result in blooms of algae. This is called eutrophication.

The Nitrogen Cycle

  • The nitrogen cycle is the biogeochemical cycle.
  • Nitrogen is a main constituent of the atmosphere encompassing about 75% of the atmospheric gases.
  • It is also a vital constituent of different organic compounds such as the vitamins, nucleic acids, pigments, amino acids, and proteins.
  • The major source of free nitrogen is the action of soil micro-organisms and associated plant roots on atmospheric nitrogen found in pore spaces of the soil.


  • Fixation is the primary step in the process of converting nitrogen, usable by plants.
  • Normally, bacteria change nitrogen into ammonium.


  • This is the process by which ammonium converted into nitrates by bacteria.
  • The plants absorb these Nitrates.


  • Through assimilation only plants get nitrogen.
  • They absorb nitrates from the soil into their roots.
  • Then nitrogen gets used in chlorophyll, nucleic acids, and amino acids.


  • This is part of the decaying process.
  • When a plant or animal expires, decomposers such that bacteria and fungi turn the nitrogen back into ammonium so it can go back into the nitrogen cycle.


  • Surplus nitrogen in the soil gets put back out into the air.
  • There are special bacteria that execute this job as well.


•            Carbon cycle is the process where carbon compounds are interchanged among the biosphere, geosphere, pedosphere, hydrosphere, and atmosphere of the earth.

Carbon Cycle Steps

Following are the major steps involved in the process of the carbon cycle:

  • Carbon present in the atmosphere is absorbed by plants for photosynthesis.
  • These plants are then consumed by animals, and carbon gets bioaccumulated into their bodies.
  • These animals and plants eventually die, and upon decomposing, carbon is released back into the atmosphere.
  • Some of the carbon that is not released back into the atmosphere eventually become fossil fuels.
  • These fossil fuels are then used for man-made activities, which pumps more carbon back into the atmosphere.


•            The water cycle is defined as continuous circulation of water from the earth to atmosphere and vice versa which is powered by the energy of the sun.

•            It shows storage and movement of water between biosphere, lithosphere and hydrosphere.

Major Water Sinks

  • Water can be stored in any of the reservoirs like atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields and groundwater.

Processes involved

  • The processes involved in the movement of water from one reservoir to another are-
  • Evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, melting and groundwater flow.
  • The driving source of energy for the water cycle is solar radiation or solar energy.
  • Evaporation and precipitation are the main processes involved in the water cycle.

Some of the processes are discussed below:

Evaporation– Water from ocean, lakes, ponds, rivers and streams evaporates by sun’s heat and energy. Water remains in vapour state in air and forms cloud.

Transpiration– Evaporation through the plant surface due to solar energy is known as transpiration. Plants also transfer a huge amount of water in the atmosphere through transpiration.

Precipitation– Cloud meets with the cold air in the mountains and above forest regions and condenses to form rain precipitates.

Condensation– It is the process by which water vapours in the atmosphere gets converted into liquid droplets.

Runoff: Water discharged from the surface is known as runoff. If it is discharged through rivers, it is known as river runoff.

  • The ocean supplies most of the evaporated water. On average 84% of water loss from the oceans through evaporations while 77% gained by precipitation.
  • Water from runoff, streams and river covers the 7% to balance evaporation deficit of oceans. On land, evaporation is 16% and precipitation is 23%.


Evidence for Rapid Climate Change

Global Temperature Rise: The planet’s average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010.

Warming Oceans: The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of more than 0.4 degrees Fahrenheit since 1969.

Shrinking Ice Sheets: The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA’s Gravity Recovery and Climate Experiment show Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period. The rate of Antarctica ice mass loss has tripled in the last decade.

Glacial Retreat: Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska, and Africa.

Decreased Snow Cover: Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.

Sea Level Rise: Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century and is accelerating slightly every year.

Declining Arctic Sea Ice: Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.

Extreme Events: The number of record high-temperature events in the United States has been increasing, while the number of record low-temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.

Ocean Acidification: Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.

Potential Effects of climate change in India

Extreme Heat: India is already experiencing a warming climate. Unusual and unprecedented spells of hot weather are expected to occur far more frequently and cover much larger areas. Under 4°C warming, the west coast and southern India are projected to shift to new, high-temperature climatic regimes with significant impacts on agriculture.

Changing Rainfall Patterns: A decline in monsoon rainfall since the 1950s has already been observed. A 2°C rise in the world’s average temperatures will make India’s summer monsoon highly unpredictable. At 4°C warming, an extremely wet monsoon that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century. Dry years are expected to be drier and wet years wetter.

Droughts: Evidence indicates that parts of South Asia have become drier since the 1970s with an increase in the number of droughts. Droughts have major consequences. In 1987 and 2002-2003, droughts affected more than half of India’s crop area and led to a huge fall in crop production. Droughts are expected to be more frequent in some areas, especially in north-western India, Jharkhand, Orissa, and Chhattisgarh. Crop yields are expected to fall significantly because of extreme heat by the 2040s.

Groundwater: Even without climate change, 15% of India’s groundwater resources are overexploited. Falling water tables can be expected to reduce further on account of increasing demand for water from a growing population, more affluent lifestyles, as well as from the services sector and industry.

Glacier Melt: Most Himalayan glaciers have been retreating over the past century. At 2.5°C warming, melting glaciers and the loss of snow cover over the Himalayas are expected to threaten the stability and reliability of northern India’s primarily glacier-fed rivers. Alterations in the flows of the Indus, Ganges, and Brahmaputra rivers could significantly impact irrigation, affecting the amount of food that can be produced in their basins as well as the livelihoods of millions of people

Sea level rise: With India close to the equator, the sub-continent would see much higher rises in sea levels than higher latitudes. Sea-level rise and storm surges would lead to saltwater intrusion in the coastal areas, impacting agriculture, degrading groundwater quality, contaminating drinking water, and possibly causing a rise in diarrhea cases and cholera outbreaks, as the cholera bacterium survives longer in saline water. Kolkata and Mumbai, both densely populated cities, are particularly vulnerable to the impacts of sea-level rise, tropical cyclones, and riverine flooding.

Apart from this food and energy security are also major concerns. Water scarcity, health hazards among the masses, and migration and political conflicts are expected to grow.

India’s response to Climate Change

National Action Plan on Climate Change (NAPCC): outlines existing and future policies and programs addressing climate mitigation and adaptation. The Action Plan identifies eight core “national missions” running through to 2017: Solar Energy; Enhanced Energy Efficiency; Sustainable Habitat; Water; Sustaining the Himalayan Ecosystem; Green India; Sustainable Agriculture; and Strategic Knowledge for Climate Change. Most of these missions have strong adaptation imperatives.

National Clean Energy Fund: The Government of India created the National Clean Energy Fund (NCEF) in 2010 for financing and promoting clean energy initiatives and funding research in the area of clean energy in the country. The corpus of the fund is built by levying a cess of INR 50 (subsequently increased to INR 100 in 2014) per tonne of coal produced domestically or imported.

Paris Agreement: Under the Paris Agreement, India has made three commitments. India’s greenhouse gas emission intensity of its GDP will be reduced by 33-35% below 2005 levels by 2030. Alongside, 40% of India’s power capacity would be based on non-fossil fuel sources. At the same time, India will create an additional ‘carbon sink’ of 2.5 to 3 billion tonnes of Co2 equivalent through additional forest and tree cover by 2030.

International Solar Alliance: ISA was launched at the United Nations Climate Change Conference in Paris on 30 November 2015 by India and France, in the presence of Mr. Ban Ki Moon, former Secretary-General of the United Nations.

Bharat Stage (BS) Emission Norms: Emissions from vehicles are one of the top contributors to air pollution, which led the government at the time to introduce the BS 2000 (Bharat Stage 1) vehicle emission norms from April 2000, followed by BS-II in 2005. BS-III was implemented nationwide in 2010. However, in 2016, the government decided to meet the global best practices and leapfrog to BS-VI norms by skipping BS V altogether.


Most natural resources, such as coal and petroleum, were formed millions of years ago. Other resources, such as sunlight, were present even before the earth was formed. Regardless, we all are dependent on these resources in some way or the other.

These resources are termed as natural resources and are very important for life on earth. Natural resources are classified into renewable resources and non-renewable resources.

Renewable Resources

The resources which cannot be exhausted even after continuous utilization are termed as renewable resources. Examples of renewable resources are the sun, wind, and tidal energy.

Non-Renewable Resources

The resources which cannot be immediately replaced once they are depleted are called Non-renewable resources. Examples of Non-renewable resources include fossil fuels, such as coal, petroleum and natural gas and rare minerals typically found in meteorites.

Comparison between Renewable and Non-renewable Resources

Examples of Renewable Energy

We can define renewable energy as those energies which can never be depleted. The importance of renewable energy is invaluable. These types of energy sources are different from fossil fuels, such as oil, coal, and natural gas. Some examples of renewable energy sources are:

  • Wind energy
  • Solar energy
  • Geothermal energy
  • Hydropower
  • Biomass energy

Sources of Renewable Energy

The sources could sustain for a longer period of time and can easily be renewed often. Sustainable sources are biomass, nuclear power, geothermal, wind energy, solar power, tidal power, and wave power.

Types of Renewable Energy

Solar Energy: The radiant light and heat energy from the sun is harnessed with the use of solar collectors. These solar collectors are of various types such as photovoltaics, concentrator photovoltaics, solar heating, (CSP) concentrated solar power, artificial photosynthesis, and solar architecture. This collected solar energy is then used to provide light, heat, and different other forms of electricity.

Wind Energy: The energy we get from winds is known as wind energy. For this, windmills have been used for hundreds of years to pump out water from the ground. We use large tall wind turbines that allow winds to generate electricity. The natural airflow on the surface of the earth is used to run the wind turbines. The modern-day wind turbines range from about 600 Kilowatt to 5 Megawatts, for commercial purposes these are rated with an output power of 1.5 to 3 Megawatts. The most preferred locations for these wind turbines to be installed are the areas which and strong and have constant airflows on offshore and sites that are at high altitudes. The power generated from wind energy in 2015 met 4% of global energy consumption.

Hydroelectricity: According to statistics, hydroelectricity generated around 16.6% of the global energy resources and constituted about 70% of all the renewable electricity. This energy is another alternative source of energy that is generated by the construction of dams and reservoirs on the flowing water, the kinetic energy from the flowing water is used to run the turbines which generate electricity. Tidal power converts the energy of tides and Wave power which captures the energy from the surface of the ocean waves for power generation. These two forms of hydropower also have huge potential in electric power generation

Geothermal Energy: It is the energy that is generated from the thermal energy which is stored in the earth. The heat energy is captured on sources such as hot springs and volcanoes and this heat is directly used by industries for heating the water and other purposes.

BioEnergy: This type of energy is derived from the biomass which is a type of biological material derived from living organisms and plant-derived materials which are called lignocellulosic biomass. Biomass can be directly used via combustion to produce heat and indirectly it can be used to convert to biofuels. Biomass can be converted to other usable forms of energy such as transportation fuels like ethanol, biodiesel, and methane gas.

Non-Renewable Energy

Non-renewable energy is energy from fossil fuels such as coal, crude oil, natural gas, and uranium. Unlike renewable energy, non-renewable energy needs human intervention to make it suitable for consumption. Fossil fuels are mainly made up of Carbon. It is believed that fossil fuels were formed over 300 million years ago when the earth was a lot different in its landscape.

Types of non-renewable energy

Non-renewable energy is mainly fossil fuels. Apart from fossil fuels, nuclear fuels are also non-renewable.

Fossil Fuels

Fossil Fuels are formed by the remains of animals and plants. Fossil fuel is divided into three categories and is stated below:

Natural Gas

The process of decomposition is longer as it is conducted to high amounts of pressure and heat.      


It is formed by the decomposition of trees, plants, and ferns which are hardened due to pressure and heat.


Due to excessive pressure, smaller organisms like zooplankton and algae are decomposed into an oil.

Nuclear fuels

The use of nuclear technology relying on fission requires naturally occurring radioactive material as fuel. Uranium is the most common fission fuel, and is present in the ground at relatively low concentrations and mined in 19 countries. Nuclear power provides about 6% of the world’s energy and 13–14% of the world’s electricity.

Non-Renewable Resources Examples

Following are the examples of non-renewable resources:

  • Coal
  • Rare earth elements
  • Petroleum products
  • Gold
  • Uranium


  • Pollution is defined as an addition of undesirable material into the environment as a result of human activities.
  • The agents which cause environmental pollution are called pollutants.
  • Pollutants may be defined as a physical, chemical or biological substance unintentionally released into the environment which is directly or indirectly harmful to humans and other living organisms.

Classification of Pollutants

According to the form in which they persist after being released into the environment:

•            Primary Pollutants: These are pollutants persisted in the environment in the form it is released from the source. e.g., Carbon Dioxide, Nitrogen Oxide, Sulphur dioxide,DDT.

•            Secondary Pollutants: These are formed from primary pollutants through change or reaction after primary pollutants being released into atmosphere. e.g., Nitrogen oxide and hydrocarbons react photochemically to produce PAN (Peroxyacyl nitrates) and Ozone is formed.

According their Nature of Degradation:

•            Biodegradable Pollutants: Those pollutants which can be broken down into simpler, harmless, substances in nature in due course of time (by the action of micro-organisms like certain bacteria) are called biodegradable pollutants.

•            Example: Domestic wastes (garbage), urine, sewage, agriculture residues, paper, wood, cloth, cattle dung, animal bones, leather, wool, vegetable stuff or plants are biodegradable pollutants.

•            Non-Biodegradable Pollutants: Those pollutants which cannot be broken down into simpler, harmless substances in nature are called non-biodegradable pollutants.

•            Example: DDT, plastics, polythene, bags, insecticides, pesticides, mercury, lead, arsenic, metal articles like aluminum cans, synthetic fibers, glass objects, iron products and silver foils are non-biodegradable pollutants.

According to their Existence in Nature:

•            Quantitative Pollutants: These are those substances normally occurring in the environment, which acquire the status of a pollutant when their concentration gets increased due to the activities of man.

•            For example, carbon dioxide, if present in the atmosphere in concentration greater than normal due to automobiles and industries, causes measurable effects on humans, animals, plants or property, and then it is classified as a quantitative pollutant.

•            Qualitative Pollutants: These are those substances which do not normally occur in nature but are manmade.

•            For example: Insecticides, Fungicides, Herbicides, DDT, etc.

According to the Origin of Pollutants:

•            Natural Pollutants: These are the pollutants emitted by natural processes.

•            Anthropogenic Pollutants: These are pollutants caused by manmade activities.

Pollution Indicator Species

•            A species of organism that can indicate an area of pollution by its presences or absence in that specific area.


  • Lichens are plants that grow in exposed places such as rocks or tree bark.
  • They need to be very good at absorbing water and nutrients to grow there.
  • Rainwater contains just enough nutrients to keep them alive.
  • Air pollutants dissolved in rainwater, especially sulfur dioxide, can damage lichens and prevent them from growing.
  • This makes lichens natural indicators of air pollution.

Indicator of Water Pollution

•            Water pollution is caused by the discharge of harmful substances into rivers, lakes and seas.

•            Many aquatic invertebrate animals cannot survive in polluted water, so their presence or absence indicates the extent to which a body of water is polluted.

Fish Survival and Water Oxygen

•            One simple way to measure the health of a given water source is to examine the survival of fish in that source of water.

•            Fish rely heavily on the dissolved oxygen in water to survive, so if oxygen levels are low due to pollution, no varieties of fish will survive.


  • Rising issue of air pollution has increasingly been becoming a serious concern, particularly in metro cities.
  • A large number of cities and towns do not meet the standards for pollutants specifically for particulate matter.
  • In a few cities including Delhi, the ambient particulate matter concentrations are much above the standards i.e. three to four times or even higher.
  • Air quality regulation and actions for abatement of air pollution is undertaken under various provisions of Air (Prevention and Control of Pollution) Act, 1981 and Environment (Protection) Act, 1985 which prescribes the mechanism and authorities for handling the issue.
  • The major impact is highlighted with reference to health of people.
  • As per the available data for Delhi and NCR for last five years, Particulate Matter (PM10 and PM2.5) concentrations are the major concern for the entire area, however a few violations are observed in NO2 concentrations in Delhi, Meerut and Faridabad.
  • The concentration of SO2 is within the standard limit at all the locations in all the last five years.
  • PM10 are inhalable coarse particles, which are particles with a diameter between 2.5 and 1O micrometers (um) and PM2.5 are fine particles with a diameter of 2.5 um or less.

Indoor Air Pollution and Health

•            Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.

Immediate Effects

  • Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant.
  • These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable.
  • Sometimes the treatment is simply eliminating the person’s exposure to the source of the pollution, if it can be identified.
  • Soon after exposure to some indoor air pollutants, symptoms of some diseases such as asthma may show up, be aggravated or worsened.
  • The likelihood of immediate reactions to indoor air pollutants depends on several factors including age and pre-existing medical conditions.
  • In some cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person.
  • Some people can become sensitized to biological or chemical pollutants after repeated or high level exposures.
  • Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution.
  • For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from the area, for example, an effort should be made to identify indoor air sources that may be possible causes.
  • Some effects may be made worse by an inadequate supply of outdoor air coming indoors or from the heating, cooling or humidity conditions prevalent indoors.

Long-Term Effects

  • Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure.
  • These effects, which include some respiratory diseases, heart disease and cancer, can be severely debilitating or fatal.
  • It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.
  • While pollutants commonly found in indoor air can cause many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems.
  • People also react very differently to exposure to indoor air pollutants.
  • Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time.

Primary Causes of Indoor Air Problems

There are many sources of indoor air pollution. These can include:

  • Fuel-burning combustion appliances
  • Tobacco products
  • Building materials and furnishings as diverse as:
    • Deteriorated asbestos-containing insulation
    • Newly installed flooring, upholstery or carpet
    • Cabinetry or furniture made of certain pressed wood products
  • Products for household cleaning and maintenance, personal care, or hobbies
  • Central heating and cooling systems and humidification devices
  • Excess moisture
  • Outdoor sources such as:
    • Radon
    • Pesticides
    • Outdoor air pollution.

Initiatives on Air Pollution Mitigation:

•            National Ambient Air Quality Standards envisaging 12 pollutants have been notified under EPA, 1986 and 115 emission/effluent standards for 104 different sectors of industries, besides 32 general standards for ambient air have also been notified.

•            Government is executing a nation-wide programme of ambient air quality monitoring known as National Air Quality Monitoring Programme (NAMP). The network consists of Six hundred and Ninety-One  manual operating stations covering Three Hundred and three  cities/towns in twenty-nine states and four Union Territories of the country.

•            With reference to Vehicular pollution the steps taken include introduction of cleaner / alternate fuels like gaseous fuel (CNG, LPG etc.), ethanol blending, leapfrogging from BS-IV to BS-VI fuel standards; ongoing promotion of public transport network of metro, buses, e-rickshaws and promotion of carpooling, streamlining granting of Pollution Under Control Certificate, lane discipline, vehicle maintenance etc.

•            National Air Quality index (AQI) was launched by the Prime Minister in April, 2015 starting with 14 cities and now extended to 34 cities.

•            A Graded Response Action Plan for control of air pollution in Delhi and NCR region has been notified. This plan specifies actions required for controlling particulate matter (PM emissions from various sources and prevent PM10 and PM2.5 levels to go beyond ‘moderate’ national Air Quality Index (AQI) category.

•            Central Pollution Control Board (CPCB) has issued a comprehensive set of directions under section 18 (1) (b) of Air (Prevention and Control of Pollution) Act, 1986 for implementation of 42 measures to mitigate air pollution in major cities including Delhi and NCR comprising of action points to counter air pollution in major cities which include control and mitigation measures related to vehicular emissions, re-suspension of road dust and other fugitive emissions, bio-mass/municipal solid waste burning, industrial pollution, construction and demolition activities, and other general steps.


•            India consists 1/25th   of world’s water resources. The total utilizable water resources of the country are assessed as 1086 km3.

Sources of Water Pollution

There are various classifications of water pollution. The two chief sources of water pollution can be seen as Point and Non Point:

•            Point Source refers to the pollutants that belong to a single source. An example of this would be emissions from factories into the water.

•            Non-Point Source on the other hand means pollutants emitted from multiple sources. Contaminated water after rains that has travelled through several regions may also be considered as a Non-point source of pollution.

Sources are:

  • Chemical fertilizers and pesticides
  • Industrial waste: Industries produce huge amount of waste which contains toxic chemicals and pollutants such as lead, mercury, sulphur, asbestos, nitrates and many other harmful chemicals.
  • Mining activities
  • Marine dumping: The garbage produce by each household in the form of paper, aluminum, rubber, glass, plastic, food if collected and deposited into the sea in some countries.
  • Accidental Oil leakage
  • Burning of fossil fuels
  • Radioactive Waste
  • Animal waste- contributes to the biological pollution of water streams
  • Construction activities
  • Leaking landfills
  • Measurement of Water Pollution

Biological Oxygen Demand (BOD)

•            BOD is the amount of dissolved oxygen needed by bacteria in decomposing the organic wastes present in water. It is expressed in milligrams of oxygen per litre of water.

•            The higher value of BOD indicates low Dissolved Oxygen content of water. Since BOD is limited to biodegradable materials. Therefore, it is not a reliable method of measuring pollution load in water.

Chemical Oxygen Demand (COD)

•            COD measures the amount of oxygen in parts per million required to oxidize organic (biodegradable and non- biodegradable) and oxidizable inorganic compounds in the water sample.

Total Organic Carbon

•            Organic matter content is typically measured as total organic carbon and dissolved organic carbon, which are essential components of the carbon cycle. The Total Organic Carbon test measures all organic carbon as CO2. Therefore, all inorganic CO2, HCO3-, etc. must be removed prior to the analysis.

•            TOC is often used when levels of organic matter (OM) are low. Total organic carbon is a good parameter to measure and actually a more accurate indication of some of the pollutants that cause the most problems than a BOD test. TOC doesn’t differentiate between that portion of organic carbon, which can be metabolized (assimilated).


  • Eutrophication refers to the addition of artificial or non-artificial substances, such as nitrates and phosphates, through fertilizers or sewage, to a fresh water system.
  • It can be anthropogenic or natural. It leads increase in the primary productivity of the water body or “bloom” of phytoplankton.
  • The overgrowth causes the loss of oxygen in the water leading to severe reductions in fish and other animal populations.
  • Eutrophication escalates rapidly when high nutrients from fertilizers, domestic and industrial wastes, urban drainage, detergents and animal, sediments enter water streams.
  • The cultural eutrophication process consists of a continuous increase in the contribution of nutrients, mainly nitrogen and phosphorus (organic load) until it exceeds the capacity of the water body (i.e. the capacity of a lake, river or sea to purify itself), triggering structural changes in the waters.

Some Water Treating Measures:

Septic Tanks and Sewage Treatments

  • Septic tanks treat sewage at the place where it is located, rather than transporting the waste through a treatment plant or sewage system.
  • Septic tanks are usually used to treat sewage from an individual building.
  • Solid material is separated depending on their density. Heavier particles settle at the bottom of the tank whereas lighter particles, such as soap scum, will form a layer at the top of the tank.
  • Biological processes are used to help degrade the solid materials. The liquid then flows out of the tank into a land drainage system and the remaining solids are filtered out.

Industrial Water Treatment:

  • In a water treatment plant, sewage goes through a number of chambers and chemical processes to reduce the amount and toxicity of the waste.
  • Primary Phase: This is where some of the suspended, solid particles and inorganic material is removed by the use of filters.
  • Secondary Phase: Involves the reduction of organic, this is done with the use of biological filters and processes that naturally degrade the organic waste material.
  • Tertiary Phase: This stage must be done before the water can be reused. Almost all solid particles are removed from the water and chemical additives are supplied to get rid of any left-over impurities.

Ozone Wastewater Treatment:

  • It is a method that is increasing in popularity. An ozone generator is used to break down pollutants in the water source.
  • The generators convert oxygen into ozone by using ultraviolet radiation or by an electric discharge field.
  • Ozone is a very reactive gas that can oxidise bacteria, moulds, organic material and other pollutants found in water. Using ozone to treat wastewater has many benefits:
    • Kills bacteria effectively.
    • Oxidises substances such as iron and sulphur so that they can be filtered out of the solution.
    • There are no nasty odours or residues produced from the treatment.
    • Ozone converts back into oxygen quickly, and leaves no trace once it has been used


•            It is an ecological approach that can be used to prevent the leaching of nitrates in soil, this in turn stops any ground water from being contaminated with nutrients.


•            The 1982, United Nations Convention on the Laws of the Sea defined Marine Pollution, “the introduction by man, directly or indirectly, of substances or energy into the marine environment which results or is likely to result in such deleterious effects as harm to living resources and marine life”.

Sources of Marine Pollution

•            The three main sources of marine pollution are direct discharge as effiuents and solid wastes from land or human activities at sea (like shipping), run off mainly via rivers, and atmospheric fall out.

Effects of Marine Pollution

  • The effects of Marine Life
  • Ghost Fishing
  • Creation of Dead Zones
  • Increase in Algal Blooms
  • Acidification of Oceans
  • Leads to loss of marine life (choking of marine life, depletion of oxygen)

Algal Bloom

  • Algal bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems, and is recognized by the discoloration in the water from their pigments.
  • Algal blooms are the consequence of Eutrophication.
  • Eutrophication is the response to the addition of nutrients such as nitrates and phosphates naturally or artificially, fertilizing the aquatic ecosystem.

Ghost Fishing

•            ‘Ghost Fishing’ is what fishing gear does when it has been lost, dumped or abandoned. Imagine a fishing net that gets snagged on a reef or a wreck and gets detached from the fishing vessel.

•            Nets, long lines, fish traps or any man made contraptions designed to catch fish or marine organisms are considered capable of ghost fishing when unattended, and without anyone profiting from the catches, they are affecting already depleted commercial fish stocks.

•            Caught fish die and in turn attract scavengers which will get caught in that same net, thus creating a vicious circle.

Dead Zones

•            Dead zones are the areas in oceans and large bodies of freshwater like lakes where the level of dissolved oxygen is too low to sustain marine life.

•            In such zones, most marine life either dies or migrates to other areas, thus turning these hypoxic zones into biological deserts. The largest dead zone is present in Gulf of Mexico.

Ocean Acidification

  • When carbon dioxide (CO2) is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals.
  • These chemical reactions are termed “ocean acidification”. Burning of fossil fuels releases CO2 and other gases which upon absorption by ocean are directly contributing to ocean acidification.
  • Release of NO2 and SO2 also cause acid rain which can contribute to ocean acidification.

Oil Spill

  • An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution.
  • The term is usually applied to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land.
  • Oil spills may be due to releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.

Oil Zapping

  • Oil Zapping is a bio-remediation technique involving the use of ‘oil zapping’ bacteria.
  • There are five different bacterial strains that are immobilized and mixed with a carrier material such as powdered corncob. This mixture of five bacteria is called Oil Zapper.
  • Oil zapper feeds on hydrocarbon compounds present in crude oil and the hazardous hydrocarbon waste generated by oil refineries, known as Oil Sludge and converts them into harmless CO2 and water.
  • The Oilzapper is neatly packed into sterile polythene bags and sealed aseptically for safe transport. The shelf life of the product is three months at ambient temperature.
  • The oil zapping bacteria was developed over a period of seven years by TERI and the project was supported by the Department of Biotechnology (Government of India) and the Ministry of Science and Technology


Article 1 of the UN Convention to Combat Desertification defines land degradation as a “reduction or loss in arid, semi-arid and dry sub-humid areas of the biological or economic productivity and complexity of rain-fed cropland, irrigated cropland, or range, pasture, forest and woodlands resulting from land uses or from a process or combination of processes, including processes arising from human activities and habitation patterns, such as:

  • soil erosion caused by wind and / or water
  • deterioration of the physical, chemical, and biological and economic properties of soil and
  • long-term loss of natural vegetation

Land degradation is the process of deterioration of soil or loss of fertility of soil.

Causes of Land Degradation

  • Population
  • Human Activities
  • Urbanization
  • Soil erosion
  • Soil contamination
  • Soil salinization
  • Soil sealing
  • Overgrazing
  • Acidification of Soil
  • Mining and quarrying activities
  • Improper crop rotations
  • Use of Chemical Fertilizer and pesticides

Sustainable Land Management (SLM)

It is crucial to minimizing land degradation, rehabilitating degraded areas and ensuring the optimal use of land resources for the benefit of present and future generations.

SLM is based on four common principles:

  • Land-user-driven and participatory approaches; 
  • Integrated use of natural resources at ecosystem and farming systems levels
  • Multilevel and multi-stakeholder involvement; and
  • Targeted policy and institutional support, including development of incentive mechanisms for SLM adoption and income generation at the local level.

Some of the methods for sustainable management of land are:

  • Management on overgrazing: Management practices like water development, placement of salt and supplements, fertilizer application, fencing, burning can control the overgrazing.
  • Managing irrigation: Irrigation system can be controlled like drip irrigation to reduce soil erosion. Using high and low salt water was most effective in maintaining the productive capacity of the clay soil.
  • Managing urban sprawl: The urban planning is the most important factor, to control the urban sprawl. Fertile field near by the urban area need to be protected by the local government rules. There should be a proper waste management system dumping of these waste generated as part of urban sprawling will degrade the land, can cause soil salinity, acidity and loss of it vegetative properties.
  • Managing mining and quarrying: The impact can be reduced by proper management of mining process, using advanced technologies rather than conventional methods. After mining by proper back filling, spreading the soil back over the top, the land can be reclaimed.
  • Managing agricultural intensification: Agricultural intensification need to be managed properly to reduce the environmental effect. This can be done through education of the farmers.


  • Noise pollution is generally defined as regular exposure to elevated sound levels that may lead to adverse effects in humans or other living organisms.
  • According to the World Health Organization, sound levels less than 70 dB are not damaging to living organisms, regardless of how long or consistent the exposure is.
  • Exposure for more than 8 hours to constant noise beyond 85 dB may be hazardous.
  • If you work for 8 hours daily in close proximity to a busy road or highway, you are very likely exposed to traffic noise pollution around 85 dB.

Various Causes of Noise Pollution


  • Most of the industries use big machines which are capable of producing a large amount of noise.
  • Apart from that, various equipment like compressors, generators, exhaust fans, grinding mills also participates in producing big noise.
  • Therefore, you must have seen workers in these factories and industries wearing earplugs to minimize the effect of noise.

Poor Urban Planning

  • In most of the developing countries, poor urban planning also plays a vital role.
  • Congested houses, large families sharing small space, fight over parking, frequent fights over basic amenities leads to noise pollution which may disrupt the environment of society.

Social Events

  • Noise is at its peak in most of the social events.
  • Whether it is marriage, parties, pub, disc or place of worship, people normally flout rules set by the local administration and create nuisance in the area.
  • People play songs on full volume and dance till midnight which makes the condition of people living nearby pretty worse.
  • In markets, you can see people selling clothes via making a loud noise to attract the attention of people.


  • A large number of vehicles on roads, airplanes flying over houses, underground trains produce heavy noise and people get it difficult to get accustomed to that.
  • The high noise leads to a situation wherein a normal person loses the ability to hear properly.

Construction Activities

  • Under construction activities like mining, construction of bridges, dams, buildings, stations, roads, flyovers takes place in almost every part of the world.
  • These construction activities take place every day as we need more buildings, bridges to accommodate more people and to reduce traffic congestion.

Household Chores

  • We people are surrounded by gadgets and use them extensively in our daily life.
  • Gadgets like TV, mobile, mixer grinder, pressure cooker, vacuum cleaners, washing machine and dryer, cooler, air conditioners are minor contributors to the amount of noise that is produced but it affects the quality of life of your neighborhood in a bad way.

Effect of Noise Pollution on Human Health

  • Hypertension is, in this case, a direct result of noise pollution caused elevated blood levels for a longer period of time.
  • Hearing loss can be directly caused by noise pollution, whether listening to loud music in your headphones or being exposed to loud drilling noises at work, heavy air or land traffic, or separate incidents in which noise levels reach dangerous intervals, such as around140 dB for adult or 120 dB for children.
  • Sleep disturbances are usually caused by constant air or land traffic at night, and they are a serious condition in that they can affect everyday performance and lead to serious diseases.
  • Child development: Children appear to be more sensitive to noise pollution, and a number of noise-pollution-related diseases and dysfunctions are known to affect children, from hearing impairment to psychological and physical effects. Also, children who regularly use music players at high volumes are at risk of developing hearing dysfunctions. In 2001, it was estimated that 12.5% of American children between the ages of 6 to 19 years had impaired hearing in one or both ears
  • Various cardiovascular dysfunctions: Elevated blood pressure caused by noise pollution, especially during the night, can lead to various cardiovascular diseases.
  • Dementia isn’t necessarily caused by noise pollution, but its onset can be favored or compounded by noise pollution.
  • Psychological dysfunctions and noise annoyance: Noise annoyance is, in fact, a recognized name for an emotional reaction that can have an immediate impact.

Effects of Noise Pollution on Wildlife and Marine Life

  • Our oceans are no longer quiet. Thousands of oil drills, sonars, seismic survey devices, coastal recreational watercraft and shipping vessels are now populating our waters, and that is a serious cause of noise pollution for marine life.
  • Whales are among the most affected, as their hearing helps them orient themselves, feed and communicate.
  • Noise pollution thus interferes with cetaceans’ (whales and dolphins) feeding habits, reproductive patterns and migration routes, and can even cause hemorrhage and death.
  • Other than marine life, land animals are also affected by noise pollution in the form of traffic, firecrackers etc., and birds are especially affected by the increased air traffic.


•            Biodiversity is the occurrence of different types of ecosystems, different species of organisms with the whole range of their variants and genes adapted to different climates, environments along with their interactions and processes.

•            Biodiversity is being depleted by the loss of habitat, fragmentation of habitat, over exploitation of resources, human sponsored ecosystems, climatic changes, pollution invasive exotic spices, diseases, shifting cultivation, poaching of wild life etc.

Effects of loss of biodiversity are:

•            The loss of biodiversity leads to depletion of genetic diversity.

•            The loss of both genetic and ecosystem diversities result in a loss of cultural diversity.

•            The alteration of the habitat results in mass extinction of particularly the endemic species.

•            The loss of a species can have deleterious effects on the remaining species in an ecosystem which lead to breakdown of biodiversity.

•            Reduced biodiversity means millions of people face a future where food supplies are more vulnerable to pests and disease and where water is in irregular or short supply.

•            The loss of plant species also means the loss of unknown economic potential, as extinct plants can hardly be harvested for food crops, fibers, medicines, and other products that forests, especially rainforests, provide.

Thus biodiversity conservation has become important.

The biodiversity conservation methodology is divided as In-situ and Ex-situ.

In-situ methods of conservation of biodiversity

•            The in-situ strategy emphasizes protection of total ecosystems. The in-situ approach includes protection of a group of typical ecosystems through a network of protected areas.

a)           Protected areas:

•            These are areas of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources.

•            These are managed through legal or other effective means. Examples of protected areas are National Parks, and Wildlife Sanctuaries.

Some of the main benefits of protected areas are:

(1)         maintaining viable populations of all native species and subspecies;

(2)         maintaining the number and distribution of communities and habitats, and conserving the genetic diversity of all the present species;

(3)         preventing human-caused introductions of alien species; and

(4)         making it possible for species/habitats to shift in response to environmental changes.

b)          Biosphere reserves:

•            Biosphere reserves are internationally recognized, nominated by national governments and remain under sovereign jurisdiction of the states where they are located.

Biosphere reserves are organized into 3 interrelated zones:

o            Core Areas: These areas are securely protected sites for conserving biological diversity, monitoring minimally disturbed ecosystems, and undertaking nondestructive research and other low-impact uses (such as education).

 O          Buffer Zones: These areas must be clearly identified, and usually surround or adjoin the Core Areas. Buffer Zones may be used for cooperative activities compatible with sound ecological practices, including environmental education, recreation, ecotourism and applied and basic research.

o            Transition, or Cooperation, Zones: These areas may contain towns, farms, fisheries, and other human activities and are the areas where local communities, management agencies, scientists, non-governmental organizations, cultural groups, economic interests, and other stakeholders work together to manage and sustainably develop the area’s resources.

•            Each biosphere reserve is intended to contribute to the conservation of landscapes, ecosystems, species and genetic variation; to foster economic and human development which is socio culturally and ecologically sustainable; to provide support for research, monitoring, education and information exchange related to local, national and global issues of conservation and development.

c)           National parks:

•            A national park is a reserve of natural or semi-natural land, declared or owned by a government, which is restricted from most development and is set aside for human recreation and environmental protection.

•            Visitors are allowed to enter, under special conditions, for inspirational, educative, cultural, and recreative purposes.

d)          Wildlife sanctuaries:

•            An area, usually in natural condition, which is reserved (set aside) by a governmental or private agency for the protection of particular species of animals during part or all of the year. An area designated for the protection of wild animals, within which hunting and fishing is either prohibited or strictly controlled. It is maintained by the state government.

e)           Sacred forests and sacred lakes:

•            A traditional strategy for the protection of biodiversity has been in practice in India and some other Asian countries in the form of sacred forests. These are forest patches of varying dimensions protected by tribal communities due to religious sanctity accorded to these forest patches.

•            In India sacred forests are located in several parts, e.g. Karnataka, Maharashtra, Kerala, Meghalaya, etc., and are serving as refugia for a number of rare, endangered and endemic taxa. Similarly, several water bodies (e.g. Khecheopalri Lake in Sikkim) have been declared sacred by the people leading to protection of aquatic flora and fauna.

Ex-situ methods of conservation of biodiversity

•            Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats. This involves conservation of genetic resources, as well as wild and cultivated or species, and draws on a diverse body of techniques and facilities.

•            Some of these include:

a)           Botanic Gardens

Botanic gardens can be defined as “public gardens which maintain collections of live plants mainly for study, scientific research, conservation and education. Botanic gardens are able

•            to rehabilitate indigenous and threatened species and restore them to protected portions of their former habitats;

•            to exploit commercially those species which are plentiful; and

•            to promote wildlife education to a broad range of target groups such as politicians, school and college students, and communities living in and around wildlife areas.

b) Translocations

•            Sometimes conservation of faunal species involves or necessitates translocation of animals. This means the movement of individuals from its natural habitat, or from captivity, to another habitat.

•            Translocations are carried out in connection with introductions or reintroductions, and should be handled with extreme caution.

•            These operations are carried out often with support from international captive breeding programs and receive the cooperation of zoos, aquaria, etc.

c)           Artificial Insemination:

•            Artificial insemination, or Al, is the process by which sperm is placed into the reproductive tract of a female for the purpose of impregnating the female by using means other than sexual intercourse or natural insemination.

d)          Somatic Cell Cloning

•            Somatic Cell Cloning holds some promise for propagating from one or a few survivors of an almost extinct species. The nucleus of a somatic cell is removed and kept, and the host’s egg cell is kept and nucleus removed and discarded.

•            The lone nucleus is then fused with the ‘deprogrammed’ egg cell. After being inserted into the egg, the lone (somatic-cell) nucleus is reprogrammed by the host egg cell. The egg, now containing the somatic cell’s nucleus, is stimulated with a shock and will begin to divide.

e)           Seed bank

•            The preservation of plant germplasm in seedbanks, (or genebanks), is one of the techniques of ex-situ conservation of plant species.

•            Storing germplasm in seedbanks is both inexpensive and space efficient. It allows preservation of large populations with little genetic erosion.

•            Seedbanks also offer good sources of plant material for biological research, and avoid disturbance or damage of natural populations.

f)            Reintroduction

•            Reintroduction of an animal or plant into the habitat from where it has become extinct is another form of ex situ conservation.

•            For example, the Gangetic Gharial has been reintroduced in the rivers of Uttar Pradesh, Madhya Pradesh and Rajasthan where it had become extinct.

Species based programmes for conservation of biodiversity

The species based conservation programmes in India are:

a) Project Tiger

•            Tigers are terminal consumers in the ecological food pyramid, and their conservation results in the conservation of all trophic levels in an ecosystem.

•            Project Tiger is a Centrally Sponsored Scheme of Government of India which was launched on the 1st of April, 1973 for in-situ conservation of wild tigers in designated tiger reserves.

•            The project aims at ensuring a viable population of Bengal tigers in their natural habitats and also to protect them from extinction, and preserving areas of biological importance as a natural heritage forever represented as close as possible the diversity of ecosystems across the tiger’s distribution in the country.

b)          Project Elephant

•            Elephant was launched in February, 1992 to assist states having free ranging populations of wild elephants to ensure long-term survival of identified viable populations of elephants in their natural habitats.

•            The project is being implemented in twelve states viz. Andhra Pradesh, Arunachal Pradesh, Assam, Jharkhand, Karnataka, Kerala, Meghalaya, Nagaland, Orissa, Tamil Nadu Uttaranchal and West Bengal.

c)           Asiatic Lion Reintroduction Project

•            The Asiatic Lion Reintroduction Project is an effort to save the Asiatic lion from extinction in the wild. The last wild population in the Gir Forest region of the Indian state of Gujarat is threatened by epidemics, natural disasters and anthropogenic factors.

•            The project aims to establish a second independent population of Asiatic Lions at the Kuno Wildlife Sanctuary in the Indian state of Madhya Pradesh.

d)          Snow Leopard Project

•            Snow leopards live in the mountain regions of central Asia. In India their geographical cover encompasses a large part of the Western Himalaya including the states of Himachal Pradesh, J&K and Uttarakhand with a sizable population in Ladakh, Sikkim and Arunachal Pradesh in Eastern Himalaya.

•            They are found at high elevations of 3000-4500 meters (9800 ft to 14800 ft.), and even higher in the Himalayas.

•            The Snow Leopard is listed as endangered on the lUCN-World Conservation Union’s Red List of the Threatened Species.

•            Keeping this in view, WWF-India initiated the project, “snow leopard conservation: An initiative”, in the states of Uttarakhand (UK) and some of the areas of Himachal Pradesh (HP) to conserve biodiversity with community participation.


  • The United Nations Convention on Biological Diversity, informally known as the Biodiversity Convention, is a multilateral treaty opened for signature at the Earth Summit in Rio De Janeiro in 1992.
  • It is a key document regarding sustainable development. It comes under the United Nations Environment Programme (UNEP).
  • 196 countries are a party to the CBD.
  • India is also a party to the Convention. India ratified it in 1994. 
    • The Biological Diversity Act, 2002 was enacted for giving effect to the provisions of the Convention.
    • To implement the provisions of the Act, the government established the National Biodiversity Authority (NBA) in 2003. The NBA is a statutory body.
  • The convention is legally binding on its signatories.
  • The Conference of Parties (COP) is the governing body of the convention. It consists of the governments that have ratified the treaty.
  • Its Secretariat is in Montreal, Canada.
  • Only two member states of the United Nations are not Parties to the CBD, namely: the USA and the Vatican.
  • In the 1992 Earth Summit, two landmark binding agreements were signed, one of them being the UNCBD. The other one was the Convention on Climate Change.
  • More than 150 countries signed the document at the Summit, and since then, over 175 nations have ratified the agreement.

Goals of the Convention on Biological Diversity

The goals of the Convention are listed below:

  1. Conservation of Biological Diversity
  2. Sustainable use of the components of the Biodiversity
  3. Fair and equitable sharing of benefits arising from the genetic resources

The idea of CBD is to develop national strategies for the conservation and sustainable use of biological diversity. In order to implement that, the convention does the following:

1.           Asserting intrinsic value of biodiversity

2.           Affirming conservation of biodiversity as a common concern of population

3.           Taking responsibility to conserve biodiversity in the State and that the state uses this biodiversity sustainably

4.           Affirming the State to put the biological resources as the Sovereign Rights of the State.

5.           Taking a precautionary approach towards conservation of biodiversity

6.           Highlighting the vital role of local communities and women

7.           Supporting access to technologies for developing countries and searching for provisions for new and additional financial resources to address the biodiversity loss in the region.


•            The traditional sources of water in Rajasthan include Nadi, Tanka, Johad, Bandha, Sagar, Samund and Sarovar.

•            The large public wells known as Kohar, Jhalra, Baori, Beri, Saagar were owned by the community.


•            In Rajasthan traditionally, maximum conservation of water is in the form of lakes.

•            Few of the lakes in Rajasthan that are world famous lakes include Lalsagar (1800), Kailana (1872), Takhatsagar (1932), and Ummedasagar (1931) Balsamand lake of Jodhpur; Jaisamand, Udai Sagar, Fateh Sagar, Rajsamand and Pichhola of Udaipur; Anasagar lake, Pushkar lake of Ajmer and Mansagar lake of Jaipur . These lakes conserved large quantities of water which is used for drinking, religious and recreational purposes.

•            A reservoir area of less than five bighas is called a talai; a medium sized lake is called a bandhi or talab; bigger lakes are called sagar or samand.


•            In Rajasthan, Step wells are locally known as Bawari and jhalara. These are sweet water aquifers getting a regular recharge through rain water.

•            Bawaris were mainly set up in cities and big towns to provide a water supply to the community through conservation of rain water.

•            Bawaris and Sarovar have remained important sources of drinking water and irrigation respectively since ancient times.

Naadi & Pokhar

•            One of the oldest and still prevalent storage structure for rainwater harvesting is naadi or dug-out village pond or tank (Pokhar). Their Agor (catchment area) is also large.

•            The water stored in a naadi acts as a source of groundwater recharge through seepage and deep percolation and is generally used for drinking by livestock and human beings.

•            Naadi construction is more prevalent in the western Rajasthan.


•            The tanka is circular or rectangular shape pond with a life span of 3-4 years, normally on bare ground to which surface runoff can be diverted.

•            The area around it is a clean catchment. The traditional tanka is constructed with lime plaster and thatched with bushes.

•            Ranisar and Padamsar tanks of Jodhpur, forest tanks of Ranthambore, Sukhsagar Tank and Kalasagar tank and Padmini tank are few famous ones.


•            It was first developed in the 15th century in the Jaisalmer district, Khadeen is a most multi-purpose method of water conservation.

•            The run-off from upland and rocky surfaces is collected in a khadeen from the adjoining valley against an embankment having a masonry water barrier for outflow of runoff excess. The standing water in a khadeen assists continuous groundwater recharge.

•            On the Khadeen bed at least one crop is cultivated even in the arid region as it retains moisture and contains fine and fertile soil.

•            In the immediate vicinity downstream the sub-surface water is extracted through bore wells.


•            To minimize the wastage of water, small well known as Kui or Beri is constructed near a water leaking and oozing tank.

•            In Bikaner, Jaisalmer and Jodhpur, Kuis are found in a large numbers.

•            Its opening is covered by strips of wood and mostly they remain kaccha. Kuis or beris are normally 5 metres (m) to 12 m deep.

•            Six or ten of kui’s when constructed together constitute a PAAR System. Rainwater harvested through PAAR technique is known as Patali paani.


•            The water of Jhalras was used in religious ceremonies, community bath and such other functions. Jhalras in Man Mandir at Jodhpur are well known.

•            They do not have their own catchment area, rather the water reservoirs receive water from soakage of tanks or lakes situated at a higher level.


•            Johads are small earthen check dams that capture and conserve rainwater, improving percolation and groundwater recharge.

•            The last twenty years have seen the revival of some 3000 johads spread across more than 650 villages in Alwar district, Rajasthan.

Traditional Roof-Water Harvesting

•            The houses in western Rajasthan during ancient times were constructed with stone and lime and the roof water was diverted to Tankas.

•            The housing complexes and institutional buildings in urban areas have large roofs and the roof-top rainwater can be conserved and used for recharge of groundwater.

•            Here an outlet pipe from the roof top to divert the water to the existing wells or special recharge wells in urban areas.


Problem with Public Health Care in Rajasthan

High out-of-pocket expenses on healthcare in Rajasthan:

•            In Rajasthan healthcare requires high out-of-pocket expenditure with about 75% of total expenses on healthcare being borne by individuals. This high out of pocket expenditure is also one of the causes of poverty and this often pushes families into poverty.

•            Additionally, many poor rural families travel to urban centres for treatment – this only pushes up the cost of availing healthcare, as they must then pay for travel and stay in the urban location

Skewed Spending:

•            A bulk of government expense is on the tertiary sector, whereas a robust primary health centre could prevent diseases from progressing and offer timely and effective medical support.

•            There is also urban skew in government spending on health – in 2016-17, while the total spend in urban areas was Rs 1,978.17 crore, it was Rs 1,991.99 for the rural areas – this despite the fact that at least 65% of the state’s population is rural.

Under budget & Under Utilization:

•            Less than 2% of the state’s GDP is allocated to healthcare sendees, which is grossly inadequate.

•            The share of health in the state budget is just about 5%; and even this allocated fund is often not used. In 2014-15, only 74% of the allocation was utilized.

 •           Even under the National Health Mission, despite its status of a mission, allocated budgets are seldom fully utilized.

Lack of Accountability:

•            The dependence on private hospitals is not only leading to diversion of huge public funds into private hands but is also resulting in severe cases of exploitation and abuse of patients by the private healthcare providers, for which there is lack of accountability.

•            There are also lack of mechanism to ensure accountability of hospitals and doctors towards quality service. Example, Rajasthan records highest rate of sterilization failures in the country.

•            There have been cases of maternal and child deaths which highlighted various dimensions of negligence and insensitivity on the part of healthcare providers.

•            Cases were highlighted wherein people had to go through tremendous hardships in seeking benefits of Bhamashah Swasthya Bima Yojana (BSBY) due to complicated eligibility criteria and how they were misled by private health facilities to squeeze more money out of their pockets.

Steps taken by Government:

•            In order to achieve further improvements in health indicators, National Immunization Program is being implemented to protect pregnant women and children below one year age from Tetanus Toxoid (TT), Bacilli Chalmette Guerin (BCG), Diphtheria Pertussis Tetanus (DPT), cholera, etc.

•            The National Health Mission (NHM) is a national effort for ensuring provision of effective healthcare through a range of interventions at individual, household, community and critically at the health system levels. In the first phase, NRHM was started in 2005 and completed in 2012 and now in the second phase NHM is being implemented till year 2017. The mission focuses on rural as well as urban health therefore, National Rural Health Mission (NRHM) and National Urban Health Mission (NUHM) are being implemented as Sub-missions of National Health Mission (NHM).

•            Many schemes or new initiatives have been implemented by the Rajasthan Government to improve the health indicators in the state in past recent years. Some of the major schemes are as follows

  • Mukhya Mantri Nislutlk Dava Yojan
  • Mukhya Mantri Nislutlk Janch Yojana
  • Rajasthan Janani Shishu Suraksha Yojna (RJSSY)
  • Rashtriya Bal Swasthya Karykram
  • Chief Minister’s BPL Jeevan Raksha Kosh scheme
  • Janani Express
  • National Mental Health Program
  • Naya Savera (Swasthaya Jeevan Ki Aur) for Doda Post Users
  • Dhanvantari 108 Toll free Ambulance Yojana
  • Bhamashaha Swasthaya Bima Yojana.
  • Aarogya Rajasthan

Public Private Partnership (PPP) in Primary Health Care

•            In June 2015, Rajasthan Government decided to run PHC public-private partnership (PPP) mode. There were 2,082 PHCs operating in Rajasthan. In first phase, 90 out of these 2082 were handed over to be run in PPP mode. Selection of private partners was done through the open bidding system and private operators were asked provide doctors, paramedics and other staff, free OPD, and 24-hour emergency scheme among other things.

e-lnitiatives in Healthcare

•            In the last few years Information Technology in health sector has been a game changer in healthcare industry and is bound to continue as the industry strives to automate medical records, improve electronic reporting, simplify daily work flows and increase cost savings by streamlining work efforts.

•            Integrated System for Monitoring of PCPNDT Act (IMPACT) Software provides the online form F for center registered to report to appropriate authority. All sonography centres in the state have been enrolled with the Medical, Health & Family Welfare department and details are available in the software. The web based Software IMPACT was launched on October 1, 2012 by the Medical Health & Family Welfare department. It provides online surveillance system of government for prevention of sex determination to save girl child.

•            Pregnancy, Child Tracking & Health Services Management System (PCTS) is a online software used as an effective planning and management tool by Medical, Health & Family Welfare department, Government of Rajasthan. The system maintains online data of more than 13,000 government health institutions in the state.

•            ASHA Soft is an online system which facilitates the health department, to capture beneficiary wise details of services given by ASHA to the community. It also provides online payment of ASHA to their bank accounts and calculation of total incentive given will be in accordance with the actual health services provided, which will help in strengthening of monitoring and management of physical & financial progress.

•           Saghan Nirikshan Abhiyaan is an designed institution-wise check list to identify the gaps in the health services at the health institution. This initiative gives access to information anywhere and anytime, direct and effective monitoring of progress, better planning and decision making, identification of gaps in health facilities, infrastructure and also in identifying best health institutions.

•            e-Aushadhi is a web-based application which deals with the management of stock of various drugs, sutures and surgical items required by different district drug warehouses of Rajasthan.

•            Providing quality health services to all citizens is the duty of the government for which national health policies have been drafted and must be implemented. The state government needs to develop complementary and alternative medicine centres, super specialty healthcare institutions to ensure qualitative delivery of healthcare at pocket-friendly cost.

•            The government should also promote development of centers of excellence for medical care, investment of private sector in medical healthcare institutions and support units (diagnostic centers, blood banks and paramedical training institutions), and also take steps towards promotion of medical tourism.


Ballistic Missile

•            A ballistic missile follows a ballistic trajectory to deliver one or more warheads on a predetermined target.

•            A ballistic trajectory is the path of an object that is launched but has no active propulsion during its actual flight (these weapons are guided only during relatively brief periods of flight).

•            Consequently, the trajectory is fully determined by a given initial velocity, effects of gravity, air resistance, and motion of the earth (Coriolis Force).

•            Longer-ranged intercontinental ballistic missiles (ICBMs), are launched on a sub-orbital flight trajectory and spend most of their flight out of the atmosphere.

Types of ballistic missiles based on the range

  • Short-range (tactical) ballistic missile (SRBM): Range between 300 km and 1,000 km.
  • Medium-range (theatre) ballistic missile (MRBM): 1,000 km to 3,500 km.
  • Intermediate-range (Long-Range) ballistic missile (IRBM or LRBM): 3,500 km and 5,500 km.
  • Intercontinental ballistic missile (ICBM): 5,500 km +

Cruise missile

•            A cruise missile is a guided missile (target has to be pre-set) used against terrestrial targets.

•            It remains in the atmosphere throughout its flight.

•            It flies the major portion of its flight path at approximately constant speed.

•            Cruise missiles are designed to deliver a large warhead over long distances with high precision.

•            Modern cruise missiles are capable of travelling at supersonic or high subsonic speeds, are self-navigating, and are able to fly on a non-ballistic, extremely low-altitude trajectory.

Types of cruise missiles based on speed

  • Hypersonic (Mach 5): these missiles would travel at least five times the speed of sound (Mach 5). E.g. BrahMos-II.
  • Supersonic (Mach 2-3): these missiles travel faster than the speed of sound. E.g. BrahMos.
  • Subsonic (Mach 0.8): these missiles travel slower than the speed of sound. E.g. Nirbhay.

Differences between Ballistic Missiles and Cruise Missiles

Ballistic MissileCruise Missile
It is propelled only for a brief duration after the launch.Self-propelled till the end of its flight.
Similar to a rocket engine.Similar to a jet engine.
Long-range missiles leave the earth’s atmosphere and reenter it.The flight path is within the earth’s atmosphere.
Low precision as it is unguided for most of its path and its trajectory depends on gravity, air resistance and Coriolis Force.Hits targets with high precision as it is constantly propelled.
Can have a very long range (300 km to 12,000 km) as there is no fuel requirement after its initial trajectory.The range is small (below 500 km) as it needs to be constantly propelled to hit the target with high precision.
Heavy payload carrying capacity.Payload capacity is limited.
Can carry multiple payloads (Multiple Independently targetable Re-entry Vehicle)Usually carries a single payload.
Developed primarily to carry nuclear warheads.Developed primarily to carry conventional warheads.
E.g. Prithvi I, Prithvi II, Agni I, Agni II and Dhanush missiles.E.g. BrahMos missiles

Integrated Guided Missile Development Programme (IGMDP)

•            IGMDP was conceived by Dr. A P J Abdul Kalam to enable India attain self-sufficiency in missile technology.

•            IGMDP was conceived in response to the Missile Technology Control Regime that decided to restrict access to any technology that would help India in its missile development program.

•            To counter the MTCR, the IGMDP team formed a consortium of DRDO laboratories, industries and academic institutions to build these sub-systems, components and materials.

Missile Technology Control Regime (MTCR)

•            MTCR an informal grouping established in 1987 by Canada, France, Germany, Italy, Japan, the United Kingdom and the United States to limit the proliferation of missiles and missile technology.

•            The MTCR seeks to limit the risks of proliferation of weapons of mass destruction (WMD).

•            MTCR places particular focus on rockets and unmanned aerial vehicles capable of delivering a payload of at least 500 kg to a range of at least 300 km.

•            The MTCR is not a treaty and does not impose any legally binding obligations.

•            IGMDP was started in 1983 and completed in March 2012.

•            Keeping in mind the requirements of various types of missiles by the defence forces, the development of five missile systems was taken up.

Prithvi: Short-range surface-to-surface ballistic missile (Prithivi means Earth Surface to Surface)

Agni: Intermediate-range surface-to-surface ballistic missile

Trishul: Short-range low-level surface-to-air missile

Akash: Medium-range surface-to-air missile (Akash means Sky Surface to Air)

Nag: Third generation anti-tank missile

After its success, the Agni missile program was separated from the IGMDP upon realizing its strategic importance.

India’s Missile Systems

Astraair-to-air80 km
Trishulsurface-to-air9 km
Akash30 km
Prithvi Air Defence (PAD)2000 km
Nagsurface-to-surface Anti-tank missile4 km
Prahaarsurface-to-surfaceSRBM150 km
BrahMosland, naval, airSupersonic Cruise Missile300 km
Nirbhayland, naval, airSubsonic Cruise Missile1000 km
K-15 Sagarikaunderwater-to-surfaceSLBM700 km
Dhanushsea-to-sea/surfaceSRBM350 km

Missile               Features


•            Astra is a beyond-visual-range (BVR) air-to-air missile (AAM).

•            In terms of size and weight, the Astra is the smallest missile developed by the DRDO.

•            It was envisaged to intercept and destroy enemy aircraft at supersonic speeds.


  • Used as anti-sea skimmer (to fly low to avoid radar) from ships against low-flying attacks.


  • It has the capability to “neutralize aerial targets like fighter jets, cruise missiles and air-to-surface missiles” as well as ballistic missiles.


  • Anti-ballistic missile developed to intercept incoming ballistic missiles outside the atmosphere (exo-atmospheric).


  • 3rd generation anti-tank ‘fire and forget’ guided missile (lock-on before launch system) where the target is identified and designated before the weapon is launched.


  • High manoeuvrability.
  • Primarily a battlefield support system for the Army.


  • It is a supersonic cruise missile developed as a joint venture between Indian and Russia.
  • It is the fastest supersonic cruise missile in the world.
  • It is the world’s fastest anti-ship cruise missile in operation.


  • Subsonic missile which is ancillary (providing necessary support) to the BrahMos range.

K-15 Sagarika 

  • It forms the crucial third leg of India’s nuclear deterrent vis-à-vis its submarine-launched ballistic missile (SLBM) capability.
  • It was subsequently integrated with India’s nuclear-powered Arihant class submarine.


  • It is capable of carrying nuclear warheads.
  • It carries forward the legacy of the K-15 Sagarika.


  • Surface-to-surface ballistic missile (SSM) variant of the K-15 Sagarika.
  • The nuclear capability of the missile enhances India’s second-strike capability.
  • It reduces the dependence on the K-15 which was built with Russian assistance.

Prithvi Missiles

All the Prithvi variants are surface-to-surface SRBMs.

NameVersionRangePayload in kg
Prithvi IArmy version150 km1000
Prithvi IIAir force version350 km500
Prithvi IIINaval version600 km1000

Agni Missiles

NameTypeRangePayload in kg
Agni-IMRBM700 – 900 km1,000
Agni-IIMRBM2,000 – 3,000 km750 – 1,000
Agni-IIIIRBM3,500 – 5,000 km2,000 – 2,500
Agni-IVIRBM3,000 – 4,000  km800 – 1,000
Agni-VICBM5,000 – 8,000 km (Testing)1,500 (3 – 10 MIRV)
Agni-VIICBM8,000 – 10,000 km (Under development)1,000 (10 MIRV)

{MIRV: Multiple Independently targetable Re-entry Vehicle}

Anti-satellite weapons (ASAT)

•            In March 2019, India successfully tested its ASAT missile.

•            The ASAT missile destroyed a live satellite in Low Earth orbit (283-kilometre).

•            As per DRDO, the missile is capable of shooting down targets moving at a speed of 10 km per second at an altitude as high as 1200 km.


Below there are some achievements of scientists in the arena of science and technology in India.

Dr. Koti Harinarayana

•            He was renowned genius scientist. It is recognized that the brain behind India’s first indigenously built combat aircraft. Tejas, which was the name given to the aircraft, saw first flight in 2001. India’s first self-made light combat aircraft was built by HAL and developed by Dr. Koti.

•            It was a result of the weakening value of the country’s soon to be obsolete Mig-21 fighter jets and, true to its name, made our defence sector’s future a lot more healthy.

C.V. Raman

•            C.V. Raman was one of the most famous scientists of India. Raman’s academic brilliance was established at a very young age. He had a pioneering work on scattering of light, C.V. Raman won the Nobel Prize for Physics in 1930. He was the first Asian and first non-White to receive any Nobel Prize in the sciences.

•            Raman also worked on the acoustics of musical instruments. He was the first to investigate the harmonic nature of the sound of the Indian drums such as the tabla and the mridangam.

•            He discovered that, when light traverses a transparent material, some of the deflected light changes in wavelength. This phenomenon is now called the Raman scattering and is the result of the Raman Effect.

Prafulla Chandra Ray

•            He was famous academician and chemist, known for being the founder of Bengal Chemicals & Pharmaceuticals, India’s first pharmaceutical company. In 1889, Prafulla Chandra was chosen an Assistant Professor of Chemistry in the Presidency College, Kolkata. His publications on miraculous nitrite and its derivatives brought him recognition from all over the world.

•            His role as a teacher was significant as he inspired to young generation chemists in India to build up an Indian school of chemistry. Famous Indian scientists like Meghnad Saha and Shanti Swarup Bhatnagar were among his students.

•            Prafulla Chandra had contributed in developing industries in India. He set up the first chemical factory in India, with very minimal resources, working from his home. In 1901, this pioneering effort resulted in the formation of the Bengal Chemical and Pharmaceutical Works Ltd.

Sir Mokshagundam Visvesvaraya

•            He was a notable Indian engineer, scholar, statesman and the Diwan of Mysore during 1912 to 1918. Sir M. Visvesvaraya was one of the most eminent engineers of India. He was best known for his contribution as the chief architect behind the construction of the Krishna Raja Sagara dam in Mandya which helped to convert the surrounding barren lands into fertile grounds for farming.

•            Visvesvaraya was knighted as the Commander of the Order of the Indian Empire (KCIE) by the British for his contributions to the society in 1915. He was a recipient of the Indian Republic’s highest honour, the Bharat Ratna for his persistent work in the fields of engineering and education. He was also awarded with several honorary doctoral degrees from eight universities in India.

•            He has the credit of inventing ‘automatic sluice gates’ and ‘block irrigation system’ which are still considered to be marvels in engineering. Each year, his birthday 15 September is celebrated as Engineer’s Day in India.

Venkatraman Radhakrishnan

•            Venkatraman was a globally distinguished space scientist and a member of the Royal Swedish Academy of Sciences. He was an internationally acclaimed astrophysicist and also known for his design and fabrication of ultralight aircraft and sailboats. His observations and theoretical insights helped the community in unravelling many mysteries surrounding pulsars, interstellar clouds, galaxy structures and various other celestial bodies.

Jagdish Chandra Bose

•            Jagdish Chandra Bose was eminent scientist. He developed the use of galena crystals for making receivers, both for short wavelength radio waves and for white and ultraviolet light. In 1895, two years before Marconi’s demonstration, Bose demonstrated wireless communication using radio waves, using them to ring a bell remotely and to explode some gunpowder.

•            He invented many of the microwave components such as waveguides, horn antennas, polarizers, dielectric lenses and prisms, and even semiconductor detectors of electromagnetic radiation in the last decade of the nineteenth century. He also proposed the existence of electromagnetic radiation from the Sun, which was confirmed in 1944.

•            After that Bose focused his attention to response phenomena in plants. He presented that not only animal but vegetable tissues, produce similar electric response under different kinds of stimuli – mechanical, thermal, electrical and chemical.

Meghnad Saha

•            Meghnad Saha belonged to Dacca, now in Bangladesh. In 1920, Meghnad Saha had developed himself as renowned physicists of the time. He has contributed in the arena of the thermal ionisation of elements, and it led him to formulate what is known as the Saha Equation. This equation is one of the basic tools for interpretation of the spectra of stars in astrophysics. His theory of high-temperature ionization of elements and its application to stellar atmospheres, as expressed by the Saha equation, is fundamental to modern astrophysics; subsequent development of his ideas has led to increased knowledge of the pressure and temperature distributions of stellar atmospheres.

Satyendra Nath Bose:

•            Satyendra Nath Bose was an outstanding Indian physicist specialising in quantum mechanics. He is of course most remembered for his excellent role played in the class of particles ‘bosons‘, which were named after him by Paul Dirac to commemorate his work in the field.

•            He is famous for “Bose-Einstein Theory” and a kind of particle in atom has been named after his name as Boson. Bose adapted a lecture on the theory of radiation and the ultraviolet catastrophe into a short article called “Planck’s Law and the Hypothesis of Light Quanta” and sent it to Albert Einstein. Einstein agreed with him, translated Bose’s paper “Planck’s Law and Hypothesis of Light Quanta” into German, and had it published in Zeitschrift für Physik under Bose’s name, in 1924.

•            This formed the basis of the Bose-Einstein Statistics. In 1937, Rabindranath Tagore dedicated his only book on science, Visva–Parichay, to Satyendra Nath Bose. The Government of India awarded him India’s second highest civilian award, the Padma Vibhushan in 1954.

Subrahmanyan Chandrasekhar:

•            He was one of the greatest scientists of the 20th century. He did commendable work in astrophysics, physics and applied mathematics. Chandrasekhar was bestowed the Nobel Prize in Physics in 1983 for Physics for his mathematical theory of black holes. The Chandrasekhar limit is named after him. He was nephew of CV Raman. His most famous work concerns the radiation of energy from stars, particularly white dwarf stars, which are the dying fragments of stars.

Vikram Sarabhai

•            Vikram Sarabhai was among distinguished scientists of India. He is considered as the Father of the Indian space program. India’s first satellite Aryabhata launched in 1975, was one of the many projects planned by him. The Satellite Instructional Television Experiment (SITE) launched in 1975-76, brought education to five million people in 2,400 Indian villages.

•            His profound cultural interests led him, along with his wife Mrinalini Sarabhai, to establish Darpana Academy, an institution devoted to performing arts and propagation of ancient culture of India.

•            He was the Chairman of the Atomic Energy Commission in 1966, Vice-President and Chairman of the UN Conference on peaceful uses of outer space in 1968, and President of the 14th General Conference of the International Atomic Energy Agency. The International Astronomical Union named a crater in the moon (in the Sea of Serenity) after him, in honour of his marvellous role to science.

APJ Abdul Kalam

•            Dr APJ Abdul Kalam is remembered as a great scientist, an inspirational leader and an extraordinary human being. As a scientist, Kalam made an effort to develop the Polar SLV and SLV-III projects between the 1970s and 1990s. Both of which proved to be success.

•            Despite the disapproval of Union Cabinet, Prime Minister Indira Gandhi allotted secret funds for these aerospace projects through her discretionary powers under Kalam’s directorship. His research and educational leadership brought him great laurels and prestige in 1980s, which prompted the government to initiate an advanced missile program under his directorship.

•            He played an intensive political and technological role when the Pokhran-II nuclear tests were conducted. Kalam served as the Chief Project Coordinator, along with R. Chidambaram during the testing phase. Photos and snapshots of him taken by the media elevated Kalam as the country’s top nuclear scientist.

•            Besides a distinguished scientist and engineer, Dr APJ Abdul Kalam served as the 11th President of India from the period 2002 to 2007. After post presidency, Kalam became a visiting professor at the Indian Institute of Management Shillong, the Indian Institute of Management Ahmedabad, and the Indian Institute of Management Indore; an honorary fellow of Indian Institute of Science, Bangalore, chancellor of the Indian Institute of Space Science and Technology Thiruvananthapuram; professor of Aerospace Engineering at Anna University; and an adjunct at many other academic and research institutions across India.

•            He had brilliant and dominant personality and he was a man of vision, who always had novel ideas for the development of the country and is also popular as the Missile Man of India.

Abhay Vasant Ashtekar

•            He is an Indian theoretical physicist. He is the Eberly Professor of Physics and the Director of the Institute for Gravitational Physics and Geometry at Pennsylvania State University. Ashtekar created variables and he is one of the founders of loop quantum gravity and its subfield loop quantum cosmology.

Aditi Pant

•            She is eminent Indian oceanographer. She was a part of the Indian expedition to Antarctica in 1983 and became the first Indian woman to visit Antarctica (along with Sudipta Sengupta).

Amal Kumar Raychaudhuri

•            He was famous Indian physicist, well-known for his research in general relativity and cosmology. His most noteworthy contribution is the eponymous Raychaudhuri equation, which demonstrates that singularities arise inevitably in general relativity and is a key ingredient in the proofs of the Penrose-Hawking singularity theorems.

Arvind Bhatnagar

•            He made significant contributions to Solar Astronomy, and founded several planetaria across India. He was the founder-director of the Udaipur Solar Observatory, and the founder director of Nehru Planetarium of Bombay.

Anna Mani

•            She was popular as an Indian physicist and meteorologist. She held the position of the Deputy Director General of the Indian Meteorological Department. She made great contributions in the field of meteorological instrumentation. She conducted research and published numerous papers on solar radiation, ozone and wind energy measurements.

Birbal Sahni

•            Birbal Sahni was a famous paleobotanist of India, who studied the fossils of the Indian subcontinent. Sahni is accredited for establishing the Birbal Sahni Institute of Palaeobotany at Lucknow in the state of Uttar Pradesh. He was a pioneer in palaeobotanical research in India and was also a geologist who took an interest in archaeology. He received several awards.

•            He was elected a Fellow of the Royal Society of London (FRS) in 1936, the highest British scientific honour, becoming the first Indian botanist to be accorded this honour. He also received the Barclay Medal of the Royal Asiatic Society of Bengal the same year. He was honoured with the Nelson Wright Medal of the Numismatic Society of India in 1945 and Sir C. R. Reddy National Prize in 1947.

Srinivasa Ramanujan

•            Srinivasa Ramanujan was a mathematician. He is extensively believed to be the greatest mathematician of the 20th Century. Srinivasa Ramanujan made major contribution to the analytical theory of numbers and worked on elliptic functions, continued fractions, and infinite series. His published and unpublished works have kept some of the best mathematical brains in the world.

Dr. Shanti Swarup Bhatnagar

•            Dr Shanti Swaroop Bhatnagar was a notable Indian scientist. He had an interest in science and engineering during early years of life. Shanti Swarup Bhatnagar had great contribution along with Homi Bhabha, Prasanta Chandra Mahalanobis, Vikram Sarabhai and others in to build post-independence Science & Technology infrastructure and in the formulation of India’s science policies.

Har Gobind Khorana

•            Har Gobind Khorana was an American molecular biologist of Indian origin. He was awarded the Nobel Prize in the year 1968 for his work on the interpretation of the genetic code and its function in protein synthesis. Dr. Khorana demonstrated how the genetic code determines all life processes by directing the synthesis of all cell proteins finally unravelled the secret of the DNA code of life.

Raja Ramanna

•            Dr. Raja Ramanna was a renowned physicist and nuclear scientis. He had a multifaceted personality and played the roles of a technologist, nuclear physicist, administrator, leader, musician, Sanskrit literature scholar, and philosophy researcher.

•            His interest was in Nuclear Physics and particularly attention to Atomic Research and he became the head of the Bhabha Atomic Research Centre at Trombay, Bombay. Dr Ramanna held several important positions in the course of his scientific career. These included the roles of Director in Babha Atomic Research Centre, Director-General in the Defence Research and Development Program, Chairman in the Atomic Energy Commission, Vice President in Indian National Science Academy, and Director in the National Institute of Advanced Studies.

•            He also played a major role in setting up the Centre for Advanced Technology at Indore and Variable Energy Cyclotron Centre at Kolkata. He was often referred to as the ‘Father of India’s nuclear program.

Harish Chandra

•            Harish Chandra was renowned Indian American mathematician and physicist who contributed fundamental work in representation theory, especially harmonic analysis on semi-simple Lie groups. He was an eminent figure in the mathematics of the twentieth century. His prestigious work related to algebra, analysis, geometry, and group theory in a fundamental and epoch-making manner that consequently became the foundation on which modern work in various fields, ranging from differential geometry and mathematical physics to number theory, is being performed.

G. N. Ramachandran

•            Gopalasamudram Narayana Iyer Ramachandran, is known for the best scientists of 20th century in India. Eminent work of G. N. Ramachandran is the Ramachandran plot, which the scientist had conceived along with Viswanathan Sasisekharan, to understand the structure of peptides.

•            Ramachandran can be accredited for bringing together into the one field of molecular biophysics the then disparate fields of X-ray crystallography, peptide synthesis, NMR and other optical studies, and physico-chemical experimentation. In 1970, he founded the Molecular Biophysics Unit at the Indian Institute of Science which was later known as the Centre of Advanced Study in Biophysics.

Prasanta Chandra Mahalanobis

•            He was renowned Indian scientist and applied statistician. He is best recalled for the Mahalanobis distance, a statistical measure. He made ground-breaking studies in anthropometry in India. He founded the Indian Statistical Institute, and contributed to the design of large-scale sample surveys.

•            He developed economic census, population census, agricultural surveys and various other large scale and in depth samples and surveys that have been esteemed around the globe.

Kotcherlakota Rangadhama Rao

•            Kotcherlakota Rangadhama Rao was popular physicists of 20th century in India. His work in spectroscopy led to the development of the Nuclear Quadrupole Resonance in Physics. Kotcherlakota Rangadhama Rao is also famous for his long association with the Andhra University in which he served as professor of Physics.

Salim Ali

•            Dr. Salim Ali had passion to study birds in detail. He was popular as an Indian ornithologist and naturalist. He was referred as “birdman of India. He became the eminent figure behind the Bombay Natural History Society after 1947 and used his personal influence to reap government support for the organisation and to create the Bharatpur bird sanctuary (Keoladeo National Park) and avert the destruction of the Silent Valley National Park. He published a research paper discussing the nature and activities of the weaver bird in 1930.

Yellapragada Subbarao

•            He was one of the greatest biologists of all times. He discovered the function of adenosine triphosphate as an energy source in the cell, and developed methotrexate for the treatment of cancer. Most of his career was spent in the United States. Subbarow is also credited with the first synthesis of the chemical compounds folic acid and methotrexate. Though, SubbaRow could not be awarded Nobel Prize, but his discoveries entitled him to be called as the father of targeted cancer chemotherapy.

Sam Pitroda

•            Satyanarayan Gangaram Pitroda generally popular as Sam Pitroda is an eminent figure. He is best known as a telecom engineer, inventor, entrepreneur and policymaker. Pitroda founded the National Innovation Council (2010), and served as the Advisor to the Prime Minister with rank of a cabinet minister on Public Information Infrastructure and Innovation, to help democratize information.

•            Pitroda had played immense role in developing India’s foreign and domestic telecommunications policies. He is considered as well-known technical professional for the telecommunication revolution in India and specifically, the ubiquitous, yellow-signed public call offices (PCO) that quickly brought cheap and easy domestic and international public telephones all over the country.

Venkataraman Ramakrishnan

•            Venkataraman, Indian born American is a senior scientist in the Structural Division at the Medical Research Council Laboratory of Molecular Biology, in Cambridge, England. He has worked in various fields of biology during the earlier part of his career. He is internationally recognized for determination of atomic structure of 30s ribosomal subunit.

•            In 2009, Ramakrishnan was honoured with the Nobel Prize in Chemistry along with Thomas A. Steitz and Ada Yonath. He received India’s second highest civilian honour, the Padma Vibhushan, in 2010.

Vijay P. Bhatkar

•            Vijay Bhatkar is one of the most admired scientists and IT leaders of India. He conceptualised India’s first supercomputer known as the PARAM 800 and unveiled in 1991. PARAM stood for parallel machine. Living up to its nomenclature of ‘supreme’, this machine, built indigenously by the Centre for Development of Advanced Computing and ranked India second after USA in the arena of supercomputing. He is credited with the creation of several national institutions, notably amongst them being C-DAC, ER&DC, IIITM-K, I2IT, ETH Research Lab, MKCL and India International Multiversity.

U.R. Rao

•            U. R. Rao is acclaimed as space scientist. He was former chairman of the Indian Space Research Organisation. He has developed the first satellite launched by India, Aryabhatta. It is the name given to the satellite which was an indigenously designed space-worthy satellite that set up tracking and transmitting systems in the orbital sphere. U.R. Rao, the chairman of ISRO at the time was the man behind the launch in 1975 that put India on the world map in terms of space research.

Subhash Mukhopadhyay

•            He is a renowned scientist born in Calcutta, India. He made remarkable discovery in medical science. He gave life to India’s first and the world’s second IVF baby. The 3rd of October 1978 saw Subhash performing India’s first In vitro fertilisation which resulted in the birth of baby Durga. Tragically, Subhash was only given a posthumous recognition of his achievements in 1986 as the West Bengal Government refused to support his ‘unethical’ methods.

Dr. Homi Jehangir Bhabha

•            He is considered as originator of the Indian Nuclear Research Programme. India accomplished nuclear capability due to the extreme efforts of Homi, thereby avoiding certain conflict simply through non-aggression treaties. This contribution of Bhabha augmented the status of India at world stage.

Dr. A. Sivathanu Pillai

•            Sivathanu Pillai is an eminent Indian scientist. He supervised the conception of indigenously developed missile systems. India’s self-sustaining missile developing programme is called BrahMOS. Dr. Pillai developed the concept of the joint venture BrahMOS, which makes India one of the few countries to develop its own ballistic missiles as well as produce and supply missiles in other key areas of the world. The start of BrahMOS led to the negation of the absolute power held by Western countries.