Mangroves grow on the bank of the Fengjiajiang River in Beihai, Guangxi Zhuang autonomous region, on Nov 25, 2020. [Photo/chinadaily.com.cn]

"The improvement work will be finished in December. To date, we have reduced the discharge of 16.5 million tons of wastewater to the river. Two year ago, the river water was rated grade V, the lowest water quality standard in China. Now it has been rated better than grade IV," said Zhang Qingxi, manager in charge of the environment improvement project from Beijing Drainage Group.

Biodiversity has increased in the area as more birds and small creatures living in mud flats can be observed, such as the spoon-billed sandpiper, a critically endangered species, and sandworm, an environmentally sensitive creature. Egrets may be the most frequently seen birds here.

"Environmental protection of the Fengjiahe River is important to achieve the city's sustainable development. I believe the gradually restored river will play a bigger role in maintaining a healthy city environment, improving people's well-being and driving urban development," Zhang added.