Beijing witnessed an 89 percent drop in airborne sulfur dioxide levels between 1998 and last year due to strict controls on coal consumption, according to the municipal environment authority.
In 2015, the annual concentration of sulfur dioxide was 13.5 micrograms per cubic meter, which was further reduced to less than 10 micrograms per cubic meter this summer, the Beijing Municipal Environmental Protection Bureau said on Monday.
The capital's municipal heating system is active from Nov 15 to March 15 each year, consuming a large amount of coal.
Beijing compares favorably to the national standard for airborne sulfur dioxide, which is 60 micrograms per cubic meter, meaning the capital has successfully controlled pollution outside the municipal heating seasons, the bureau said.
It attributed this to a reduction in coal consumption and the replacement of coal-fired boilers used for heating in thousands of households.
Coal now takes up about 14 percent of the city's energy consumption mix, the bureau said.
It is estimated that Beijing's coal consumption will be further cut to 9 million metric tons by 2020, as cleaner alternatives are promoted.
