The Cooum River is the shortest classified river draining into the Bay of Bengal. This river is about 72 KMs in length, flowing 32 KMs in the Urban part and the rest in rural part. The river is highly polluted in the urban area (Chennai), which we can call as "Polluted Part of the Cooum River", and the rest as "Unpolluted Part of the Cooum River". Along with the Adyar River running parallel to the south, the river trifurcates the city and separates Northern Chennai from Central Chennai.