Polluted Dianchi Lake, Yunnan's largest, takes steps toward cleanliness

Dianchi Lake, the biggest lake in Yunnan province, achieved its best water quality in at least three decades last year thanks to the local government's pollution control and ecological restoration efforts.

Covering about 310 square kilometers in Kunming, the provincial capital, Dianchi Lake used to be one of the most polluted in the country because of the rapid local urbanization and industrialization process in the 1980s, according to Wu Zhaoyang, deputy director of the lake administration

Wu said the city began its environmental monitoring of the lake in 1988. At that time, it didn't even reach the lowest Grade V standard in China's five-tier water quality assessment system.