Vembanad Lake is the longest lake in India and the largest lake in the state of Kerala. It is also one of the largest lakes in India. It is known by different names in different localities, such as Punnamada Lake in Kuttanad, or Kochi Lake in Kochi. The Port of Kochi is located around two islands (the Willingdon Island and Vallarpadam) in a portion of this lake known as the Kochi Lake. The celebrated Nehru Trophy Boat Race is conducted in the Kuttanad region, known as the Punnamada Lake.
Information based on http://en.wikipedia.org/wiki/Vembanad_Lake