Bengaluru, Mar 7 (PTI): Hundreds of dead fish were washed ashore today at Ulsoor lake, a popular boating site here, raising concerns about water pollution in the city.

Residents living in and around the lake were in for a shock as they found the fish heaped around, raising unbearable stink in the water body.

Several residents, who complained about the stink, said sewage from the drain flowing into the lake due to a breach in a bund had depleted oxygen levels causing the large fish kill and authorities concerned had done nothing despite complaints.

"We are not surprised...we have been warning authorities from the last two years..sewage water is getting mixed with the lake water due to a breach in a bund..," a resident said.

A tourism spot, Ulsoor lake had been choked with water hyacinth in recent years, with government launching clean-up efforts.

The incident comes even as there is a growing concern by environmentalists over polluted lakes, exemplified by the thick froth and flames from the Yamlur lake that caused ripples in the city last year.

The cause for the large fish kill was not known.