Only 73 of 338 Chinese cities subject to air quality monitoring met the national standard for clean air in 2015, according to the Ministry of Environmental Protection.
It made the revelation on Thursday in its annual Environment Condition Communique.
Environmental authorities observed precipitation in 480 cities and detected acid rain in 22.5 percent of them last year, according to the communique.
They also conducted tests at 338 cities' drinking water sources, and found the water in nearly 3 percent of them was unfit for drinking.
There were also some improvements in 2015. For example, the number of deaths in floods dropped 76 percent from the previous year, while the number of residents affected by floods and the area affected by floods declined 46 percent and 45 percent respectively.
Forest coverage has reached 21.6 percent in China, with its total forested area ranking fifth in the world, according to the communique.
