Green duckweeds are covering up the upper branches of Huangpu River and moving towards the water areas in Shanghai, Xinhua News Agency reported on Wednesday.

This summer the Huangpu River, the main source of drinking water for Shanghai, is suffering from an unprecedented breakout of duckweeds, according to the municipal government, and the city is striving to control the outbreak.

By June 22, as many as 2,195 tons of duckweeds have been removed.

Duckweed is a small flowering plant that floats on water surface. Coverage of duckweeds will reduce water evaporation compared to having a clear surface.

(Xinhua News Agency June 26, 2008)