Geography – India

India comprises four well-marked physical divisions:

1. The Himalayan Range: The Himalayas, amongst the youngest fold mountains in the world, surround India on the north, north-west and north-east forming an arc. It is part of the Great Mountains of the north which run along the northern border of India has two parts: the Karakoram and the Himalayas. The Karakoram has a number of ranges like Zaskar, Ladakh and Pir Panjal with mainly river Jhelum flows in this region. The Himalayas has three important ranges: Himadri, Himachal and Siwalik, about 2400 km in length and varying in width from 240 to 320 km.

(i) The Greater Himalayas (northern range, average approx. 6000 m in height and contain three highest mountains on earth: Mount Everest (8848 m), K2 or Mount Godwin Austin (8611 m) and Kanchenjunga (8598 m). Such high altitudes admit travel to a few passes only, notably Shipki La [in Satluj valley.north-east of Kalpa (Kinnaur)] and Jelep La and Nathu La [on the main Indo-Tibet trade route through the Chumbi valley, north-east of Darjeeling]. Greater Himalayas or Himadri, under perpetual snow, contains several glaciers which are sources of rivers like Ganges and Yamuna. The core of this part of Himalayas is composed of granite.

(ii) The Lesser Himalayas (averaging 1500 to 5000 m in height) or Himachal (averaging 1500 to 5000 m in height), are situated south of the Greater Himalayas, the average width is of 50 km. While the Pir Panjal range forms the longest and the most important range, the Dhaula Dhar and the Mahabharat ranges are also prominent ones. This range

consists of the famous valley of Kashmir, the Kangra and Kullu Valley in Himachal Pradesh. Many health resorts are situated on the southern sole of the mountain range. These ranges are mainly composed of highly compressed and altered rocks.

(iii) The Outer Himalayas (or the Southern Himalayas), (averaging between 900 m and 1200 m in height lie between the Lesser Himalayas and the Indo-Gangetic plains). These discontinuous ranges joins the Lesser Himalayas in the extreme east. The longitudinal valley lying between Lesser Himalaya and the Shiwaliks are known as Duns. Dehra Dun, Kotli Dun and Patli Dun are some of the well-known Duns. These ranges are composed of unconsolidated sediments brought down by rivers from the main Himalayan ranges located farther north. These valleys are covered with thick gravel and alluvium.

The eastern extension of eastern Himalayas is called Poorvanchal Mountains. The Brahmaputra marks the eastern most boundary of the Himalayas. Beyond the Dihang gorge, the Himalayas bend sharply to the south and spread along the eastern boundary of India. They are known as the Purvanchal or the Eastern hills and mountains. These comprise of the Patkai Hills, the Naga Hills, Manipur Hills and the Mizo Hills.

2. The Northern Plains or the Indo-Gangetic Plains: One Formed by the valleys of the rivers Ganges and Brahmaputra, with a length of about 2400 km and width ranging between 240 km to 320 km. These plains occupy one-third of India’s land surface and form the most fertile region.

The Great plains comprises of levelled land to the south of the Great Mountains of the North made up of fertile allvium soil. It consists of the Indus Basin, Gang a Basin and Brahmaputra Basin. River Indus and its tributaries— Jhelum, Chenab, Ravi, Beas and Sutlej rise beyond the Himalayas. The tributaries of River Ganga either rise in the Himalayas or in the Peninsular Plateau. Yamuna, Ghaghara, Gandak, Kosi and Tista rise in the Himalayas. Chambal, Sindh, Betwa, Son, Ken and Damodar rise in the Peninsular Plateau. River Brahmaputra rises beyond the Himalayas.

3. The Deccan Plateau: Lying south of the northern plains, the plateau is flanked by mountain ranges called the Eastern and Western Ghats. It is geographically the oldest region of India, with rocks which are 3000 to 5000 million years old. The higher Deccan peaks reach over 2500 m which include the Nilgiri Hills.

4. Coastal Plains: The northern portion of the western coastal plain is called the Konkan and the southern portion is called the Malabar coast. The eastern coastal strip is known as the Coromandel Coast.

The Aravallis and the Deccan Mountains

(a) The Aravallis: The oldest mountain range in India. The highest peak in this range is Guru Shikhar at Mount Abu, rising to 1722 m, lying near the border with Gujarat.

(b) The Vindhya Range: Separate the southern part of India from the northern part. Extending 1050 km, the average elevation of these hills is 3000 m.

(c) The Satpura Range: Lies between the rivers Narmada and Tapti. It extends to 900 km with many peaks rising above 1000 m. It runs parallel to the Vindhya Range, which lies to the north and these two east-west ranges divide the Indo-Gangetic plain from the Deccan Plateau located north of River Narmada.

(d) Western Ghats: Run along the western edge of India’s Deccan Plateau and separate it from a narrow coastal plain along the Arabian Sea. The range runs approximately 1600 km and average elevation is about 915 to 1220 m.

(e) Eastern Ghats: Though not as tall as the Western Ghats, some of its peaks are over 1000 m in height. Average elevation is about 610 m. The Nilgiri Hills in Tamil Nadu lies at the junction of the Eastern and Western Ghats.

ISLANDS

There are two groups of Islands:

1. Andaman and Nicobar Group: The northern cluster of 204 small islands comprise the Andamans and the southern cluster of 19 small islands are the Nicobar islands.
2. Lakshadweep: A group of 27 coral islands scattered in the Arabian Sea 300 km west of Kerala.

DESERTS

The Thar Desert, also known as the Great Indian Desert, is a large, arid region in the north-western part of the Indian subcontinent and forms a natural boundary running along the border between India and Pakistan. It extends from the Sutlej River and has the Indus River on the west. The Aravalli forms the main landmark to the south-east of Thar Desert with Rann of Kutch, the salt march, sometimes included in Thar is on its south. It lies mostly in the Indian State of Rajasthan (touches the southern portion of Haryana and Punjab and northern Gujarat). The Cholistan Desert adjoins the Thar Desert spreading into Pakistani Punjab province.