Chennai i/ˈtʃɛnnaɪ/ (formerly known asMadras i/məˈdrɑːs/ or /-ˈdræs/) is the capital city of the Indian state of Tamil Nadu. Located on the Coromandel Coast off theBay of Bengal, it is the biggest cultural, economic and educational centre in South India. Chennai is known as the "Detroit of South Asia" for its automobile industry. It is the fourth-largest city and fourth-most populous metropolitan area in the country and 36th-largest urban area in the world. Chennai is the most visited city in India by foreign tourists, and 38th most visited city in the world."The quality of living survey" rated Chennai as the safest city in India.Chennai attracts about 45% of health tourists from abroad arriving in India, so the city is termed as "health capital of India".
The city is host to the third-largest expatriatepopulation in India after Mumbai and Delhi, with 35,000 in 2009 and steadily climbing to 82,790, in 2011. Tourism guide publisher Lonely Planet named Chennai as one of the top ten cities in the world to visit in 2015. Chennai is ranked as a beta-level city in the Global Cities Index  and was ranked the best city in India by India Today in the 2014 annual Indian city survey.Chennai has also been named in the "hottest" cities to live in for 2015 by BBCamong global cities with a mixture of both modern and traditional values. National Geographic ranked Chennai as world's 2nd best food city and Chennai was the only Indian city to feature in the list. Chennai was also named as the 9th-best cosmopolitan city in the world by Lonely Planet.
The Chennai Metropolitan Area as recently as January 2015 has been ranked the fourth-largest economy in India, and the third-highest GDP per capita. As a growing metropolitan city in a developing country, Chennai confronts substantial pollution and other logistical and socio-economic problems. Chennai has been selected as one of the 20 Indian cities to be developed as asmart city under PM Narendra Modi'sflagship Smart Cities Mission.
DistrictChennai, Kanchipuramand Tiruvallur[A]Former name MadrasNative Lang Tamil Established1639Government • TypeMayor–Council • BodyGreater Chennai Corporation • MayorSaidai Duraisamy • Deputy MayorP. Benjamin • Corporation CommissionerB Chandra Mohan IAS • Police CommissionerT.K. Rajendran IPSArea • Megacity426 km2 (164.8 sq mi) • Metro1,189 km2 (426 sq mi)Elevation6 m (20 ft)Population (2011) • Megacity7,088,000 • Rank4th • Density17,000/km2(43,000/sq mi) • Metro9,173,521 • Metro rank4thDemonym(s)ChennaiiteTime zoneIST (UTC+05:30)Pincode(s)600 XXXArea code(s)+91-44Vehicle registrationTN-01 to TN-14, TN-18, TN-22, TN-85UN/LOCODEIN MAAOfficial languageTamilSpoken languagesTamil, EnglishWebsiteChennai Corporation