Water from the nation’s longest river is flowing into Taihu lake at a rate of 150 cubic meters per second, up from the earlier 127 cubic meters per second, and the lake has received a total of 190 million cubic meters of Yangtze water since May 11, according to the water ministry’s Taihu Valley Administration.

The Wuxi Tap Water Supply Company is also pumping a large amount of active carbon and potassium permanganate into the lake in an attempt to purify the water.

"But the method can not solve the problem as the water quality is so bad," said Zhou Shengdong, director of the company’s quality monitor center.

Citizens are complaining that the tap water is so putrid that they can not wash with it.

"The tap water stinks and has a yellowish color, the whole family has not taken a shower for two days," said Shi Xiuying, a resident in Nanchang District.

The water level in three old wells in Shi’s neighborhood is dropping quickly as residents rush to stock up.

A large algae-chocked area is currently visible near Nanquan, a major water plant for Wuxi Tap Water Supply Company, where some workers are trying to remove the algae.

"The water quality is far beyond the limits of drinking water treatment. It should be treated in sewage plants," said Zhou Liusong, a worker at the Nanquan Water Plant.

The water supply from Xiaowanli Tap Water Company in Wuxi, an economically dynamic city 128 km from Shanghai with a population of more than 5 million, has not resumed after supply was halted on May 22 when the Taihu lake started to stink with a blue-green algae bloom.

On May 28, the water supply from Gonghu Tap Water Firm also became smelly and black as it contained five milligrams of ammonia and nitrogen per liter and was unable to dissolve oxygen.

The Taihu water administration added that the water supply from the Xidong Tap Water Company which supplies 20 percent of the downtown urban population was not affected.

The water pollution resulted in panic buying of bottled water and bread in Wuxi, which prompted the price of an 18-liter bottle of water sold by street peddlers to rise from eight yuan to 50 yuan by Wednesday night.

A downtown Walmart outlet strictly rationed sales of 500 milliliter bottles of water to a 24-bottle box per person.

"Bottled water is now sold out and we are transferring 1,000 boxes from nearby cities," said Shangguan Xiaoling, a member of Walmart’s staff.

Blue-green algae is a form of aquatic plant that occurs naturally in rivers, lakes, damp soil, tree trunks, hot springs and snow. "Bloom" is the common term used to describe an increase in the number of algal cells to a point where they discolor the water, form scum, produce unpleasant tastes and odors, affect shellfish and fish populations or otherwise create a nuisance and seriously reduce water quality.

Taihu Lake is a scenic attraction famous for its aquatic life, including whitebait, shrimps, lily and water chestnuts. But today the lake is a smelly shadow of its former self.

Initial investigations show the water level of Taihu Lake is at its lowest in 50 years this summer due to continuous high temperatures and lack of rainfall, which have led to an excess of nutrients in the water.

Local authorities are closely monitoring supplies of bottled water in 10 supermarkets and have allocated more bottled water from neighboring cities.

The city’s pricing bureau issued a circular on Wednesday to ban water price hikes. Vendors who deliberately drive up water prices may face fines of up to 300,000 yuan (39,200 U.S. dollars), it said.

The local environmental agency is closely monitoring the water quality around the clock. Yang Weize, secretary of the Wuxi City Committee of the Communist Party of China, vowed on Wednesday to guarantee safe drinking water "at all costs".