Physical Landscape

The geological history of India started with geological evolution nearly 4.57 billion years ago. Indian geological formations consist of the Deccan trap, the Gondwanaland the Viviyan and those that originated in Pleistocene, Tertiary and Pr-Cambrian periods. Conventionally the country is divided into three physio graphic regions viz., the Himalaya and associated mountain chain, the Indus-Ganga-Brahmaputra plains and the Peninsular plateau including the coasts and the islands. The Himalayan Mountain covers about 5, 00,000 sq kms of land and extends over 2500 kms from the Karakorum in thewest to the Myanmar in the east. Its width is about 240 kms. World’s 14 highest peaksand few large rivers are located in the Himalaya. Indus-Ganga-Brahmaputra plains located in the northern part of the country, extends for 3200 kms from the River Indus in the west to Brahmaputra in the east. Its width varies between 150-300 kms. The senile peninsular plateau in the south is triangular in shape and has some of the oldest mountains of world with elevation varying between 600 and 800 mts. The Islands includethe Lakshwadeep (36 coral Islands) and the Andaman (200 Islands) and Nikobar (19
Islands). The soils in India fall into seven categories, namely the alluvial soils, Black soils, Red soils, Literate soils, Forests soils, Mountain soils and Desert soils.

Climate and Water Resources

India is situated in the Northern hemisphere and the tropic of cancer divides the countryinto roughly two equal parts. The southern part enjoys a low temperature range while theNorth is cold in winters and warm for greater part of the year exhibiting much greater
range in its temperature. Though generally described as a tropical country, Indiaexperiences varied climatic conditions in different regions. The north is more affected bya continental climate while the south has more maritime influence (Arabian Sea, Bay ofBengal and Indian Ocean). Much of the rain is a gift of the monsoon and is primarilyorographic. The annual rainfall of 116 cms is only marginally higher than the global
mean of 99 cms. Spatial distribution of rainfall in India is characterized by great
unevenness. While Mawsynram, located in the southern face of Meghalaya plateau
receives the highest annual rainfall in world, India also has one of the driest regions of


world i.e. Jaisalmer located in the western part of the country. Generally rainfall decreases from east to west.

India has 4 per cent of the freshwater reserve of the world. The annually‘replenishable’ groundwater has been estimated at 432 billion cubic meters (BCM). TheGanga basin has the highest potential followed by the Godavari and the Brahmaputra.
The Indo-Gangetic alluvial plain with an area of around 25,000 km2 is one of the largest
groundwater reservoirs in the world. Of the total groundwater of India, only 30 per centhas been harnessed. Overuse of groundwater in almost all the states of India has led to
ground water depletion in large parts of the country. In certain areas, like Punjab, thelevel of groundwater exploitation is over 98 per cent.

India is rich in terms of surface water wealth. It has some of the largest rives ofworld e.g. the Brahmaputra (2900 Kms), the Indus (2810kms) and the Ganga (2525 Kms). Besides, there are many other large river basins, with basin area of more than 20,000 km2. Some of its lakes are internationally known e.g. Chilka, Wular, Sambhar etc. Rainfall is the main source of surface water in India. It receives about 4000 BCM of water from precipitation. Of this, monsoon rainfall accounts for about 3000 BCM. Thetotal utilizable water is about 690 BCM in the country.

India is one of the most disaster prone areas of world. Nearly 57 per cent of thecountry’s land is prone to earthquakes included in the seismic zones III-IV. About 8 percent of the land is vulnerable to cyclones of varying intensity. About 68 per cent of thenet sown area and 5 per cent of the total land are vulnerable to droughts and floods (40
million ha). India alone accounts for 20 per cent of the deaths caused by floods in theworld.