The environment of Three-river-source area in northwest China's Qinghai Province improved in 2017 with more green coverage and better air quality, according to an provincial environment report.

The three rivers involved in the source area refer to the Yangtze, Yellow, and Lancang (Mekong) rivers. The environment was damaged by human activity such as overgrazing, but has improved in recent years.

Last year, over 95 percent of days in the area had fairly good air quality or better and grass coverage there reached 74 percent.

Sanjiangyuan became a nature reserve in 2000 and a national park will open in 2020.