Adyar river which traverses a distance of 40 km originates from Chembarambakkam, Chengai-MGR District, enters Madras City near Nandambakkam. It flows in the West-East direction for a distance of 13.5 km before joining the Bay of Bengal near Thiru-vi-ka Bridge. It collects the surplus water from more than 200 tanks of the Chembarambakkam group and other irrigation tanks nearby, which have a combined catchment area of 331 sq. miles. During the colonial period, there were large estates and garden houses along the Adyar river. The estuary of the Adyar attracts a wide variety of birds. The river has formed a backwater called the creek due to the formation of sand bar at the mouth. This creek is a natural channel which carries tidal water back into the sea. In 1987, the forest department declared the estuary as a protected area.
The release of sewage into the Adyar River by commercial establishments has been checked and sewer mains flowing towards the river from residential areas of Saidapet and Ekkaduthangal were being diverted to the sewage network for treatment and disposal, according to Chennai Metrowater.