The front of a cadmium pollution belt on the Xiangjiang River in the central-southern province of Hunan, passed the provincial capital Changsha early Sunday morning.
The provincial environmental protection bureau said the content of cadmium in the city's drink water source has already been lowered to twice the national standard as against the former four times the standard on Saturday.
As of Sunday, all the water provided for civil use has reached the national standards.
The pollution was caused by the improper operations of a silt clearing project in Xiawan Harbor, Zhuzhou, said Jiang Yimin, director of the environmental bureau.
Zhuzhou Water Conservancy Investment Co. Ltd. started the project on December 23, 2005 without permission from environmental departments, according to the bureau.
The company dammed the mouths of waste draining pipes at the Zhuzhou Smelting Plant on January 4, diverting polluted water, containing cadmium waste, into two lakes. The pollution then flowed into the Xiangjiang River.
The pollution has affected the two neighboring cities of Changsha and Xiangtan.
By press time, emergency anti-pollution measures had been activated with the help of experts from the State Environmental Protection Administration (SEPA).