The plan comes amid mounting official urgency about curbing chronic pollution in China's rivers and lakes. The problem has left millions of people without clean water and disrupted city water systems. Lake Tai is among several lakes where blooms of blue-green algae, blamed on pollution, have disrupted water supplies this year.

Some types of the algae can produce dangerous toxins. The algae bloom on Lake Tai in June prompted the suspension of running water in and around the major city of Wuxi for six days, forcing five million people to rely on bottled water.

The algae covered up to a third of the 2,400sq km lake, a popular tourist attraction that has become badly polluted as the Wuxi area developed into a centre for manufacturing and high technology.

Regulators responded by ordering the closure of chemical plants that dumped waste into the lake.