A yacht rows at the Erhai Lake in Dali Bai Autonomous Prefecture, southwest China's Yunnan Province, Jan. 4, 2015. The Erhai Lake, covering 253 square kilometers and being the second largest fresh water lake in Yunnan Province, is named as the "mother lake" by local people. Two major outbreaks of blue algae in the Erhai Lake between 1996 and 2003 triggered problems in drinking water supply. Thanks to the efforts of local government in controlling pollution in the famous plateau lake and improving the local environment, the water quality of the lake has been improved. (Xinhua/Lin Yiguang)