Environmental workers check the water quality of the Yangzonghai Lake, which covers 186 square kilometers and flows through the counties of Chengjiang, Chenggong and Yiliang in Yunnan, on September 20, 2009. [Xinhua photo]
![Environmental workers check the water quality of the Yangzonghai Lake, which covers 186 square kilometers and flows through the counties of Chengjiang, Chenggong and Yiliang in Yunnan, on September 20, 2009. [Xinhua photo]](http://images.china.cn/attachement/jpg/site1007/20090603/001109b42f730b9026bb1f.jpg "Environmental workers check the water quality of the Yangzonghai Lake, which covers 186 square kilometers and flows through the counties of Chengjiang, Chenggong and Yiliang in Yunnan, on September 20, 2009. [Xinhua photo]")
