Coorinates: 13°05′N 80°16′E / 13.09, 80.27 Chennai (Tamil: சென்னை, formerly known as Madras (help·info), is the capital of the Indian state of Tamil Nadu. Located on the Coromandel Coast of the Bay of Bengal, Chennai has an estimated population of 7.5 million (2007), making it the fourth largest metropolitan city in India.