Photo taken on Dec. 8, 2012 shows the landscape scenery of Erhai Lake in Dali Bai Autonomous Prefecture, southwest China's Yunnan Province. 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. 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/Qin Qing)

Photo taken on Dec. 8, 2012 shows the landscape scenery of Erhai Lake in Dali Bai Autonomous Prefecture, southwest China's Yunnan Province. 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. 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/Qin Qing)

Photo taken on Dec. 8, 2011 shows the landscape scenery of Erhai Lake in Dali Bai Autonomous Prefecture, southwest China's Yunnan Province. 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. 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/Qin Qing)

A villager does the washing beside the Erhai Lake in Dali Bai Autonomous Prefecture, southwest China's Yunnan Province, Dec. 6, 2011. 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. 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/Qin Qing)