BEIJING — The density of hazardous fine particle matter (PM2.5) stood at 58 micrograms per cubic meter on daily average at the end of last month, 13.4 percent lower than the same period last year, the local authority said.

“As of Dec 10, seriously polluted days this year reduced to 21, from 58 in 2013, and only four seriously polluted days were recorded so far this winter,” said Liu Baoxian, deputy director of the Beijing Municipal Environmental Monitoring Center.

In a bid to make air cleaner, Beijing has been eliminating coal-fired boilers and upgrading gas-fired boilers with low nitrogen combustion technology.

The density of sulfur dioxide has been reduced to 8 micrograms per cubic meter as of November from 28 microgram per cubic meter in 2013. The city eliminated 4,453 coal-fired boilers this year.

As of Nov 15, Beijing finished work replacing coal with clean energy — electricity or gas — in 700 villages, according to the municipal commission of rural affairs.

Over the past five years, about 99.8 percent of the city’s coal-fired boilers have been removed, cutting the use of coal by nearly 9 million tons.

Since 2013, about 900,000 households in 2,036 villages have shifted from coal to clean energy, cutting the use of coal by 2.7 million tons per year.