Photo taken on Oct. 27, 2020 shows the view of a wetland park in north China's Tianjin. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds.

Tourists walk at a wetland park in north China's Tianjin, Oct. 27, 2020. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds.

Photo taken on Oct. 27, 2020 shows the view of a wetland park in north China's Tianjin. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds. (Photos: Xinhua)

Photo taken on Oct. 27, 2020 shows the view of a wetland park in north China's Tianjin. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds.

Eastern spot-billed ducks rest at a wetland park in north China's Tianjin, Oct. 27, 2020. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds.

Photo taken on Oct. 27, 2020 shows the view of a wetland park in north China's Tianjin. The wetland was originally a saline-alkali wasteland. After renovation, its environment has been effectively restored, providing a suitable habitat for birds.