With an estimated population of 7.5 million, Chennai is the fourth largest metropolitan city in India and one of the largest metropolitan areas in the world. It is the capital of the Indian state of Tamil Nadu. The region around Chennai has served as an important administrative, military, and economic center since the first century. After being ruled by various South Indian dynasties, the Portuguese arrived in 1522 and built a port called São Tomé after the Christian apostle St. Thomas who is said to have preached in the area between 52 and 70 CE.

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Wikipedia article on Chennai