Dianchi Lake is the largest freshwater lake on the Yunnan-Guizhou Plateau in southwestern China. However, in the late 1980s, it became murky because of the industrial and domestic waste. It has been suffering from surges of green algae.

To protect the lake, both the central and provincial governments implemented a series of measures to restore its lost splendor after decades of severe pollution. After over 30 years of endeavor, water quality of Dianchi Lake has been much improved. 

It remained to grade IV in the first half of 2019. In China, water quality is assessed in five grades ranges from I to V, with V being the lowest. 

Fisherman Zhang Kaidi pours shrimps he caught into his fishing boat on Dianchi Lake in Kunming. Dianchi Lake officially opened for fishing on October 16. To protect the local ecological environment, only whitebaits and small shrimps are allowed to be fished during the 30-day fishing season this year, and harvest of any other aquatic products are prohibited.