The ambient air quality around Mount Qomolangma, known in the West as Mount Everest, is good, reaching the country's Class I standard, according to Tibet's 2020 environmental bulletin released by the region's Department of Environment and Ecology on Thursday.

In 2020, the overall ambient air quality of the region was excellent. The proportion of days with excellent air quality was 99.4 percent, and the ratio of days with excellent ambient air quality in Lhasa, the region's capital, was 100 percent, ranking second among 168 key cities in China, the bulletin said.

In 2020, water quality in the region's major rivers and lakes held steady in good condition, reaching the environmental quality standards as stipulated by the central government.

Water quality in the region's key rivers — the Jinsha, Nujiang and Lancang — as well in the lakes of Namtso, Bangong and Yardrok Yutso are up to Class II standards.

According to the regional department, Tibet will work to maintain the ratio of days with excellent air quality above 98 percent to 2025, and it will ensure the water quality in the region's key rivers and lakes reaches or exceeds the Class III standard.