GEOGRAPHY

The territory controlled by India, the major portion of the Indian subcontinent, lies between latitudes 6° and 36° N, and longitudes 68° and 98° E. The country sits atop the Indian tectonic plate, a minor plate within the Indo-Australian Plate.

India's defining geological processes commenced seventy-five million years ago, when the Indian subcontinent, then part of the southern supercontinent Gondwana, began a northeastwards drift—lasting fifty million years—across the then unformed Indian Ocean. The subcontinent's subsequent collision with the Eurasian Plate and subduction under it, gave rise to the Himalayas, the planet's highest mountains, which now abut India in the north and the north-east. In the former seabed immediately south of the emerging Himalayas, plate movement created a vast trough, which, having gradually been filled with river-borne sediment, now forms the Indo-Gangetic Plain. To the west of this plain, and cut off from it by the Aravalli Range, lies the Thar Desert

Topographic map of India.

India's coast is 7,517 kilometres (4,700 mi) long; of this distance, 5,423 kilometres (3,400 mi) belong to peninsular India, and 2,094 kilometres (1,300 mi) to the Andaman, Nicobar, and Lakshadweep Islands. According to the Indian naval hydrographic charts, the mainland coast consists of the following: 43% sandy beaches, 11% rocky coast including cliffs, and 46% mudflats or marshy coast.

Major Himalayan-origin rivers that substantially flow through India include the Ganges (Ganga)  the second largest river on the Indian subcontinent by discharge. The 2,510 km (1,560 mi) river rises in the western Himalayas in the Indian state of Uttarakhand. It has long been considered holy by Hindus and worshiped as the goddess Ganga in Hinduism. It has also been important historically: many former provincial or imperial capitals (such as Patliputra, Kannauj, Kara, Allahabad, Murshidabad, Baharampur and Kolkata) have been located on its banks. The Ganges Basin drains 1,000,000-square-kilometre (390,000 sq mi) and supports one of the world's highest densities of humans. The average depth of the river is 52 feet (16 m), and the maximum depth, 100 feet (30 m). And the Brahmaputra, both of which drain into the Bay of Bengal. Important tributaries of the Ganges include the Yamuna and the Kosi, whose extremely low gradient causes disastrous floods every year.