India, with an area of 3.3 million sq. km, is a subcontinent. The peninsula is separated from mainland Asia by the Himalayas . The country lies between 8° 4' and 37° 6' north of the Equator and is surrounded by the Bay of Bengal in the east, the Arabian Sea in the west and the Indian Ocean to the south. 

The Himalayas form the highest mountain range in the world, extending 2,500 km over northern India . Bounded by the Indus river in the west and the Brahmaputra in the east, the three parallel ranges, the Himadri, Himachal and Shivaliks have deep canyons gorged by the rivers flowing into the Gangetic plain. 

 River Systems

The rivers may be classified as follows: (a) the Himalayan, (b) the Deccan , (c) the coastal and (d) the rivers of the inland drainage basin. The Himalayan rivers are generally snow-fed and flow throughout the year. During the monsoon months (June to September), the Himalayas receive very heavy rainfall and the rivers carry the maximum amount of water, causing frequent floods. The Deccan rivers are generally rain-fed and, therefore, fluctuate greatly in volume. A very large number of them are non-perennial. The coastal rivers, specialty on the west coast, are short and have limited catchment areas. Most of these are non-perennial as well. The rivers on the inland drainage basin are few and ephemeral. They drain towards individual basins or salt lakes like the Sambhar or are lost in the sands, having no outlet to the sea. 

 Climate

The Himalayan range in the north acts as the perfect meteorological barrier for the whole country. Despite the country's size and its varied relief, the seasonal rhythm of the monsoon is apparent throughout. Although much of northern India lies beyond the tropical zone, the entire country has a tropical climate marked by relatively high temperatures and dry winters. 

 Natural Vegetation

The Himalayan region, which is rich in vegetative life, possesses varieties that can be found practically from the tropical to tundra regions. Only the altitude influences the distribution of vegetation. In the rest, of the country, the type of vegetation is target determined by the amount of rainfall. Outside the Himalayan region, the country can be divided into three major vegetation regions: the tropical wet evergreen and semi-evergreen forests, the tropical deciduous forests, and the thorn forests and shrubs.