BEIJING, March 13 (Xinhua) -- China reported improved air and water quality as well as reduced carbon dioxide emissions in 2020 amid the country's efforts in green development, an official report showed.

Last year, the percentage of days with good air quality was 87 percent in 337 cities at and above the prefecture level, up 5 percentage points year on year, said the report released by the Ministry of Ecology and Environment.

The average concentration of hazardous airborne particles PM2.5 was 33 micrograms per cubic meter, down 8.3 percent year on year, while that of PM10 fell 11.1 percent year on year to 56 micrograms per cubic meter.

Data collected at 1,940 monitoring water sections reported improvement of China's water quality, with the proportion of surface water with fairly good quality -- at or above Grade III in the country's five-tier water quality system -- rising 8.5 percentage points year on year to 83.4 percent.

In the same period, the proportion of surface water below Grade V, the lowest level, stood at 0.6 percent, down 2.8 percentage points from 2019, said the report.

In 2020, China's carbon dioxide emissions per unit of GDP dropped 1 percent over one year earlier. The country also achieved the target of lowering the emissions per unit of GDP by 18 percent during the 2016-2020 period, with the figure of 2020 down 18.8 percent from 2015.