After more than 200 birds died on the shores of a lake in the Inner Mongolia autonomous region, residents accused chemical plants of widespread pollution, Beijing News reported on Friday.

Some of the dead birds are listed, such as egrets and tadorna ferrugineas.

They died near the Chahannao'er Lake in Ordos, which used to be a natural alkaline lake.

However, after taking in polluted water from local chemical plants, it has become a waste-water lake which covers nearly 10 square kilometers.

The report said some of the water is black with thick bubbles floating to the surface.

A 60-year-old resident said that before chemical plants moved in a decade ago the place was a popular oasis full of birds' nests and eggs every spring.

Over the past decade, flocks of birds have gradually disappeared and thousands have died there recently. The local government regularly collect these dead birds and bury them nearby.

The chemical plants used to publicly drain contamination into the lake, which was stopped under the pressure of complaints lodged by residents.

They later started to discharge polluted water through hidden pipelines at night, a local shepherd said.

In addition, the companies extract groundwater extensively, wich has drawn the water table down.

Mou Guangfeng, an evaluator at the Ministry of Environmental Protection, was quoted as saying that over-exploitation of groundwater is disastrous for the ecosystem.

zhangyu1@chinadaily.com.cn