Chennai (until 1996 - Madras) is a city in southern India, the administrative center of Tamil Nadu. The fourth largest city in the country (after Mumbai, Delhi, Calcutta), the 41st largest urban metropolitan area in the world. It was founded in 1639 on the Coromandel Coast (southeast coast of India, washed by the waters of the Bay of Bengal).
The city is located in the north-east of Tamil Nadu, on the coastal lowlands (average height 6 m, maximum - 60 m above sea level). Along the coast stretches the 12-kilometer beach Marina beach - one of the longest in the world. Chennai cross two rivers - Kuwam in the center and Adyar in the south. Kuvam is very heavily polluted, Adyar is periodically cleaned, and a small reserve has been created in its estuary. A 4-kilometer Buckingham Canal, connecting both rivers, was dug parallel to the shore. In the west of the city there are lakes Red Hills, Sholawaram and Chembarambakkam, supplying the city with drinking water, since groundwater is highly saline. The problem of water supply is very acute, for its solution it is planned to build a water pipe from the Krishna river (Andhra Pradesh state) and a desalination plant in Chennai.