The Adyar or Adayar, originating near the Chembarambakkam Lake in Kanchipuram district, is one of the three rivers which winds through Chennai (Madras), Tamil Nadu, India, and joins the Bay of Bengal at the Adyar estuary. The 42.5-kilometre (26.4 mi) long river contributes to the estuarine ecosystem of Chennai. Despite the high pollution levels, boating and fishing take place in this river. The river collects surplus water from about 200 tanks and lakes, small streams and the rainwater drains in the city, with a combined catchment area of 860 square kilometres (331 sq mi). Most of the waste from the city is drained into this river and the Cooum.