Beijing's environment authority said Monday that the capital city's PM2.5 density, an indicator of air pollution, has dropped by over 20 percent during the first 10 months of the year from the same period last year.

The average density of PM2.5, airborne particles smaller than 2.5 microns in diameter, was 69.7 micrograms per cubic meters in Beijing, down 21.8 percent year on year. Meanwhile, the density of PM10, sulfur dioxide, and nitrogen dioxide fell by 21 percent, 39.8 percent and 17.1 percent respectively, according to the Beijing environmental protection bureau.

During the first nine months, Beijing's number of days with good air quality grew by 31 from last year, and the number of days with heavy pollution dropped by 16.

The bureau attributed the improvement to air pollution control measures and favorable weather conditions.

The city has removed some 280,000 old cars from roads, closed 315 polluting companies, and increased green area by 6,000 hectares during the first 10 months.

Fang Li, deputy head of the bureau, said the city will intensify its monitoring of air quality and enhance controls on activities such as burning leaves, barbecues, and fireworks during the last two months of the year.