Chennai /ˈtʃɛnaɪ/ (also known as Madras Listeni/məˈdraːs/) is the capital city of the Indian state of Tamil Nadu. Located on the Coromandel Coast off the Bay of Bengal, it is the biggest industrial and commercial centre in South India,and a major cultural, economic and educational centre. Chennai is known as the "Detroit of India" for its automobile industry. It is the sixth-largest city and fourth-most populous metropolitan area in the country and 31st-largest urban area in the world. The city is the secondary financial hub in the country, after Mumbai. The city is host to the third-largest expatriate population in India after Mumbai and Delhi, with 35,000 in 2009 and steadily climbing to 82,790, in 2011. Chennai is the only city in South Asia and India to figure in the "52 places to go around the world" by The New York Times. Tourism guide publisher Lonely Planet has 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 BBC among 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 the the 9th best cosmopolitan city in the world by Lonely Planet. As a growing metropolitan city in a developing country, Chennai confronts substantial pollution and other logistical and socio-economic problems. With a gross domestic product (GDP) of $66 billion, Chennai is ranked sixth in India by overall GDP contribution.