Vembanad is the longest lake in India, as well as the largest lake in the state of Kerala. The lake has an area of 230 square kilometers and a maximum length of 96.5 km. Spanning several districts in the state of Kerala, it is known as Vembanadu Lake in Kottayam, Vaikom, Changanassery, Punnamada Lake in Alappuzha, Punnappra, Kuttanadu and Kochi Lake in Kochi. Several groups of small islands including Vypin, Mulavukad, Maradu, Udayamperoor, Vallarpadam, Willingdon Island are located in the Kochi Lake portion. Kochi Port is built around the Willingdon Island and the Vallarpadam island. Kuttanad, also known as The Rice Bowl of Kerala, has the lowest altitude in India, and is also one of the few places in world where cultivation takes place below sea level. Kuttanad lies on the southern portion of Vembanad. The Nehru Trophy Boat Race is conducted in a portion of the lake. High levels of pollution have been noticed at certain hotspots of the Vembanad backwaters. The Government of India has identified the Vembanad wetland under the National Wetlands Conservation Programme. Geography and hydrography The Vembanad lake is 96.5 km long, making it the longest lake in the country. The area of Vembanad backwater shrinked from 230 km2 in 1968 to 179.25 km2 as of 1983. The lake is bordered by Alappuzha, Kottayam, and Ernakulam districts. It is situated at the sea level, and is separated from the Laccadive Sea by a narrow barrier island. Canals link the lake to other coastal lakes in the north and south. The lake surrounds the islands of Pathiramanal, Perumbalam and Pallippuram. The Vembanad Lake is approximately 14 kilometers wide at its widest point. The lake is a part of the Vembanad-Kol wetland system which extends from Alappuzha in the south to Azheekkode in the north, making it by far, India's longest lake at just over 96.5 km in length. The lake is fed by 10 rivers flowing into it including the six major rivers of central Kerala namely the Achenkovil, Manimala, Meenachil river, Muvattupuzha river, Pamba and Periyar. The total area drained by the lake is 15,770 km², which accounts for 40% of the area of Kerala. Its annual surface runoff of 21,900 Mm accounts for almost 30% of the total surface water resource of the state. The most popular location on the shores of the lake is the Kumarakom Tourist Village situated on the east coast