Adyar (Tamil: அடையார்) or Adayar, originating near the Chembarambakkam Lake in Chengalpattu district, is one of the two rivers which winds through Chennai (Madras), South India, and joins the Bay of Bengal at the Adyar Estuary. The 42.5 km-long river contributes to the estuarine ecosystem of Chennai. Despite the high pollution levels, boating and fishing take place in this river. The river takes in surplus water from about 50 tanks and lakes, small streams and the rainwater drains in the city. Most of the waste from the city is drained into this river and the Cooum.