A dead oyster is seen left on the dry bottom of the Chirui Lake at Shiping County, southwest China's Yunnan Province, March 24, 2010. [Xinhua]

Young volunteers clear sludge at the bottom of the Chirui Lake at Shiping County, southwest China's Yunnan Province, March 24, 2010. The local government took the present opportunity of sustaining severe drought, which began to ravage the region since last autumn, to clear sludge of the lake. [Xinhua]