BEIJING - Through an increasing effort to combat pollution, China has achieved remarkable results in pollution control, according to a white paper released Friday by the State Council Information Office.

Having announced a battle against pollution, the country has improved the quality of air, water and soil, said the white paper titled "Biodiversity Conservation in China."

In 2020, China's average concentration of ambient particulate matters, or PM2.5, declined by 28.3 percent from 2015, while the percentage of days with good air quality rose by 5.8 percentage points from 2015.

The combined proportion of state-controlled water sections with good-quality surface water was 83.4 percent last year, up by 17.4 percentage points from 2015, while that of good-quality offshore waters was 77.4 percent in terms of area, up by 9 percentage points from five years earlier, the white paper said.

In 2020, the safe utilization rate of contaminated arable land and that of contaminated land both exceeded 90 percent, it said.