SHANGHAI, June 4 -- WUXI Mayor said the city is considering raising the threshold of pollutant discharge into Taihu Lake after an outbreak of blue-green algae in it cut clean water supply to local residents last week, Legal Daily reported today.

"The water crisis spurred our resolution to treat the pollution in Taihu," Wuxi Mayor Mao Xiaoping said today. "To raise the threshold of pollutant discharge will top our agenda."

Taihu has been heavily polluted as a result of industry, agriculture and domestic waste.

Huang Xuanwei, the former chief engineering of Taihu management bureau, said one-ton wastewater requires nine-ton clean water to dilute, while Taihu only has polluted water to "dilute" the wastewater.

Xu Qianqing, a researcher of Chinese Academy of Engineering, said the water quality in Taihu keeps worsened because the threshold is too low.

"Water discharged from plants is still worse than the national standard," Xu said.

China's State Council, or cabinet, said yesterday that energy efficiency and pollutant-discharge reduction should be set as indices for assessing economic and social development in all localities and the performance of government and company leaders.

An earlier report said pollution levels exceed the standard in 84 percent of China's 634 wastewater discharge outlets.

Tap water was drinkable again yesterday afternoon in Wuxi city, Jiangsu Province.

The quality of water from all tap-water companies in Wuxi is stable and has met drinking standards, local health authorities said.

But urban residents in Wuxi, with a population of two million, still depend on bottled water for cooking and drinking as polluted water remains in pipes.

The officials urged residents to let taps run until all contaminated water is gone.