Kolavai Lake is the second largest lake in the Kanchipuram District after the Madhuranthagam Lake. Once a very huge lake, now it has been reduced to nearly half the size due to the creation of the Mahindra World city on its banks and other encroachments. Kolavai lake is well known for its perenniality: There are no records of going dry in summers. It even supplies water to industries in Chennai when the lakes in Chennai go dry. The lake is now being polluted due to the rapid urbanisation of Chengalpattu. The early morning sunrise and the moon howering above the lake over its waters in the night are scenic to the eyes.