Adyar River
The river is almost stagnant except during the rain season. Rapid industrialisation and urbanisation has led to severe contamination of this river. However, the river gets just 10 per cent of the untreated sewage being let into the three principle waterways of Chennai daily, with the other two, namely, the Buckingham Canal and the Cooum River, taking the major share (60 per cent and 30 per cent, respectively).