Experts have urged the government to strengthen efforts to deal with water pollution in the wake of the Wuxi water crisis.

The Wuxi government has stressed that the incident was "an irresistible natural disaster". But Ma Jun, director of the Institute of Public and Environmental Affairs, a NGO environment watchdog in Beijing, had a different view.

"Natural factors like the low water level and hot weather are only inducing factors to the incident, not the root," he said. "The root of this sudden algal bloom growth spree is the water pollution"

China is becoming a huge industrial workshop for the rest of the world, sacrificing its environment including clean water, he said.

The government said it had gone to great lengths to protect its water supplies.

In Taihu Lake alone, the government has poured at least 10 billion yuan into schemes to make the lake water cleaner and ordered enterprises to stop spewing waste into it. But investigations have revealed more than 300 enterprises at the upper reach of Taihu Lake have breached the government's orders. Among them are big companies such as Wuxi Sharp Electronic Components Co Ltd, found emitting pollutants into the lake in 2006, and Suzhou Samsung Electronics Co Ltd, in 2005.

"We are very concerned whether these companies have redressed their problems or they simply paid some fines and continued discharging waste water into the lake," Ma said.