Three years ago, President Xi Jinping tasked officials in Yueyang, Hunan province, with protecting the Yangtze River watercourse, including Dongting Lake, China's second-largest freshwater lake.

About half the lake, an essential part of the Yangtze River system, lies in Yueyang and it plays a vital role in maintaining the river's ecology and biological diversity.

Xi gave his instruction to the officials on April 25, 2018, while on a trip to inspect environmental protection and economic development efforts along the Yangtze, Asia's longest river.

The city, which the Yangtze flows through for 163 kilometers, has made significant efforts to protect its environment and restore its ecology.

Yueyang has implemented a 10-year fishing ban along the river and in the lake, cracked down on illegal sand mining, eliminated 32 odorous water bodies and closed 39 illegal docks along the Yangtze, according to local government figures.

Eighteen government officials were appointed "river and lake chiefs" to regularly inspect all major rivers and lakes in the city, and it also hired 2,173 river and lake chiefs at various levels to oversee all rivers and lakes in the region.

The efforts have paid off, with 95.7 percent of Yangtze River water in the city meeting the Level II standard or above last year and 100 percent rated Level III or better. The water quality of Dongting Lake was close to the Level III standard last year.

China has a five-tier system for classifying water quality, ranging from Level I, which is suitable for drinking after minimal treatment, to Level V, which is severely polluted.

The city government plans to invest a total of 11.6 billion yuan ($1.8 billion) to build a complete sewage treatment system to further improve the water quality, with 4.58 billion yuan already having been spent.

Yueyang resident Zhang Shanju, 76, said people did not want to go near Dongfeng Lake in the city's downtown area in the past because it smelled bad and was filled with garbage.

However, he said, the lake's environment has improved markedly in recent years and residents now take strolls or exercise on its shores.

"The improved environment has also significantly increased our sense of happiness, and we can look forward to cleaner water and a healthier environment," Zhang said.

Now that it is cleaner, the much bigger Dongting Lake is attracting huge numbers of birds. More than 288,000 water birds－a decade high－spent the winter at Dongting Lake last year.

The East Dongting Lake National Nature Reserve was also home to some 120 Yangtze finless porpoises and more than 200 rare milu deer, both under first-class protection in China.