Beijing reported the best air in five years in January with the help of anti-pollution measures and favorable weather.
The average concentration of PM2.5, smaller airborne particles more damaging to health, stood at 34 micrograms per cubic meter, said the Beijing Municipal Environmental Protection Bureau Wednesday.
This is the lowest monthly level since 2013 when Beijing started publishing its air quality data. The last monthly low was made in August 2017 when the PM2.5 reading stood at 38 micrograms per cubic meter.
The readings in the 16 districts fell between 51 percent and 74 percent year on year, it said.
Twenty-five days, or 80.6 percent of all, reported good air quality with air quality index (AQI) below 100.
Beijing and its neighboring regions have taken tough measures to fight air pollution, including closures of highly polluted firms, shifting to clean energy for winter heating and limiting construction work and industrial production in winter.
Meanwhile, the frequent cold fronts helped disperse air pollution, the bureau said.
The Chinese capital has intensified measures in recent years to improve its air quality and has achieved remarkable results.
The average density of PM2.5 in Beijing was 58 micrograms per cubic meter last year, meeting the target set by the State Council, as well as being 20.5 percent less than in 2016.
Beijing plans to spend more than 19 billion yuan (US$3 billion) to fight air pollution this year.
China has set a target to reduce the average PM2.5 level by at least 15 percent in the cities around the Beijing-Tianjin-Hebei region between October 2017 and March 2018, compared to the year-earlier level.