People wear masks at Tian'anmen Square in Beijing on Monday, as smog returned to the city after a short time of relief.[Photo/China Daily]

The capital had 198 days with good air quality, an increase of 12 days from 2015, and 39 serious pollution days, down by 7 days, it said.

Though average density of PM2.5, particulate matter measuring less than 2.5 microns, fell to 73 micrograms per cubic meter in 2016, this was still 109 percent higher than the national standard.

Since 2013, PM2.5 density in the city has dropped 19 percent.

Average levels of sulfur dioxide, nitrogen dioxide and PM10 decreased by 28.6 percent, 4 percent and 9.8 percent respectively on 2015.

The city has made great efforts to deal with pollution in recent years, including shutting down polluting plants and encouraging use of natural gas to replace coal.

Coal consumption in Beijing has fallen by as much as 57 percent in the past three years. The city burned less than 10 million tonnes of coal in 2016.

Currently, Beijing's per capita coal consumption is less than one sixth of the national average, while its per capita natural gas use is six to seven times the national level.

The key to completely eliminating serious air pollution lies in adjusting industrial structure and optimizing energy structure, said Zhang Dawei, head of the Beijing Environmental Protection Monitoring Center.