In December, at a news conference held by the Hefei city government, Ding Zhisong, director of the Hefei Ecology and Environment Bureau, showcased two pictures of birds to reporters.

One was a photo of a Dalmatian pelican, an animal under first-class national protection, in the waters of Chaohu Lake, and the other was a picture of a magnificent flock of birds shaped like a giant whale flying in the sky.

"The choice of birds is the most genuine barometer of ecology," said Ding.

In recent years, every winter, the area around Chaohu Lake, the country's fifth-largest freshwater lake and surrounded by wetlands, has become a paradise for migratory birds.

So far, 338 species of birds have been observed in the Chaohu Lake basin, according to the latest official records.

With the accelerating industrialization and urbanization, the watershed of the lake, which is located in the provincial capital of Anhui, had once been subject to an explosively rising population and worsening water pollution.

In 1996, the central authorities listed the lake and its feeder rivers as key targets for pollution control.

The city has taken several measures to protect the environment around the lake, including banning fishing and converting agricultural fields into wetlands.

The central authorities listed Hefei in 2017 as one of 28 cities for a pilot program to increase the capacity to adapt to climate change through a combination of measures.

The measures included building more climate-resilient infrastructure and facilities and improving the roles of urban wetland ecosystems to address climate change, according to documents of the pilot program.

Since the start of the Anhui Chaohu Lake Watershed Integrated Protection and Restoration Project in 2021, a total of 47 sub-projects have been implemented, with a cumulative investment of 10.5 billion yuan ($1.5 billion) and 8.9 billion yuan in funds allocated by the end of 2025, according to data from the Hefei Finance Bureau.

The project has completed ecological restoration over 950 square kilometers and wetland restoration over 417 hectares.

Among them, the sub-project for ecological restoration of the mining area in southern Lujiang county, where the Lujiang alum mine is located, was selected as a third-batch typical case by three ministries, including the Ministry of Finance, in December 2025.

Since 2021, the water quality of local rivers flowing to the Chaohu Lake has remained at or above Class III in China's five-tier surface water quality evaluation system.

During the 14th Five-Year Plan (2021-25) period, the water quality of the entire Chaohu Lake has continuously improved from Class V in 2018, stabilizing at Class IV, with the average in the first half of 2025 reaching the "good" level of Class III.

The water quality flowing out of Chaohu Lake into the Yangtze River has consistently met Class II standards, with Chaohu Lake delivering nearly 4 billion cubic meters of high-quality Class II water to the Yangtze River each year, according to the local government.

Liu Chang contributed to this story.