Local residents flocked to buy bottled water and bread after a blue-green algae bloom appeared on Tuesday in Taihu Lake, making the water smell unpleasant.
The price of an 18-liter bottle of water sold by street peddlers had risen from eight yuan to 50 yuan on Wednesday night.
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 rain, which caused an excess of nutrients in the water.
The city government is planning to artificially induce rain on Thursday or Friday to dilute lake water, and the provincial government has agreed to divert more water from the Yangtze River to the lake.
Local authorities are closely monitoring the supplies of the bottled water in 10 supermarkets and have allocated more bottled water from neighboring regions.
The affected population is mostly in the city districts, but the local government is still counting the exact number who have been affected by the blue-green algae bloom.
Local authorities are closely monitoring the water quality around the clock and Yang Weize, secretary of the Wuxi Municipal Committee of the Communist Party of China, vowed on Wednesday to guarantee safe drinking water "at all costs."
Blue-green algae is a simple aquatic plant life 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 can discolor the water, form scum, produce unpleasant tastes and odors, affect shellfish and fish populations, or otherwise create a nuisance and seriously reduce the water quality.