DANJIANGKOU, Dec. 12 (Xinhua) -- This year marks the 10th anniversary of the operation of China's South-to-North Water Diversion Project, which was initiated to address China's regional water imbalance.

The project has three routes. The middle route, the most prominent one, starts at the Danjiangkou Reservoir in central China's Hubei Province and runs across Henan and Hebei before reaching Beijing and Tianjin.

Since the middle route began supplying water in December 2014, strict regulations have been enacted to reduce pollutants, and the city has organized more than 450 volunteer groups to protect the water quality. As a result, water quality in the Danjiangkou Reservoir rarely falls below the second class on China's five-tier quality scale for surface water.