Chennai is the capital city of the Indian state of Tamil Nadu. Located on theCoromandel Coast off the Bay of Bengal, it is the biggest industrial and commercial centre in South India,[6] and a major cultural, economic and educational centre. Chennai is known as the "Detroit of India" for its automobile industry.

Chennai, sometimes referred to as the "Gateway to South India,"[44][45] is located on the south–eastern coast of India in the north–eastern part of Tamil Nadu on a flat coastal plain known as the Eastern Coastal Plains. Its average elevation is around 6.7 metres (22 ft),[46] and its highest point is 60 m (200 ft).[47] Two major rivers meander through Chennai, the Cooum River (or Koovam) through the centre and theAdyar River to the south. Cooum is one of the most polluted rivers in the whole South of India and serves as potential health hazard to the people living in and around the river. A third river, the Kortalaiyar, flows through the northern fringes of the city before draining into the Bay of Bengal, at Ennore.

Chennai has a tropical wet and dry climate (Köppen: Aw). The city lies on the thermal equator[58][59] and is also on the coast, which prevents extreme variation in seasonal temperature. The hottest part of the year is late May to early June, known regionally as Agni Nakshatram ("fire star") or as Kathiri Veyyil,[60] with maximum temperatures around 35–40 °C (95–104 °F). The coolest part of the year is January, with minimum temperatures around 15–22 °C (59–72 °F). The lowest recorded temperature was 13.8 °C (56.8 °F) on 11 December 1895 and Januar 29, 1905. The highest recorded temperature was 45 °C (113 °F) on 30 May 2003. The average annual rainfall is about 140 cm (55 in).

Tourism and Hospitality
With temples, beaches and centres of historical and cultural significance, including the UNESCO Heritage Site of Mahabalipuram, Chennai remains the most visited city in India. Chennai has been the most visited Indian city since 2008, in terms of foreign tourists arrival.[182] In 2011, Chennai was ranked 41st in global top 100 city destination ranking, with 3,174,500 tourists, a 14 percent increase from 2010, up from 650,000 in 2007. In 2009, Chennai attracted the highest number of foreign tourists in the country. The city serves as the gateway to the southern part of India with tourists landing in the city and starting their trip to the rest of the region. Top foreign nationals visiting the city includes those from Sri Lanka, Malaysia, and Singapore, followed by the United Kingdom, France and the United States. In 2010, the figure of foreign tourist arrival increased by 40 percent in the first half of the year.[183] About 830,620 domestic tourists arrived in Chennai in March 2011. Currently, the city has 21 luxury hotels in the five-star and five-star deluxe categories,[184] with over 4,500 rooms in the inventory.

Chennai's economy has a broad industrial base in the automobile, computer, technology, hardware manufacturing and healthcare sectors. As of 2012, the city is India's second largest exporter of information technology (IT) and business process outsourcing (BPO) services.[203][204] A major part of India's automobile industry is based in and around the city thus earning it the nickname "Detroit of India".[7][44][205][206] It is known as the Cultural Capital of South India [207] and is the most visited city in.