Capital marks progress in decadelong fight against air pollution

Beijing's annual average PM2.5 concentration fell below 30 micrograms per cubic meter for the first time in 2025, a milestone officials described as historic, with experts urging continued, technology-backed emission reductions.

Beijing recorded an average PM2.5 level of 27 micrograms per cubic meter last year, marking the first time it has dropped below the 30-microgram benchmark since monitoring began, according to data released at a news conference on Sunday. Only one day was classified as heavily polluted, defined as PM2.5 readings above 150 micrograms per cubic meter, down from 58 such days in 2013.

PM2.5 is particulate matter with a diameter of 2.5 micrometers or less, which are air pollutant particles that can invade even the smallest airways.

"Heavily polluted days have been essentially eliminated in Beijing," said Liu Baoxian, deputy director of the Beijing Municipal Ecology and Environment Bureau, calling the result a landmark achievement at the close of the 14th Five-Year Plan (2021–25) period.

Throughout 2025, good air quality was recorded on 348 days, 144 days — or nearly five months — more than in 2013, according to the bureau.

The figures mark a dramatic turnaround for a city that once grappled with severe and frequent smog. In 2013, Beijing's annual average PM2.5 concentration stood at 89.5 micrograms per cubic meter, and air pollution was a major issue that impeded urban development and affected public well-being.

To reverse the trend, Beijing launched an intensive "blue sky defense" campaign targeting emissions from vehicles, coal use, industry, construction dust and everyday urban sources, while strengthening joint prevention and control across the Beijing-Tianjin-Hebei region.

According to He Kebin, an academician at the Chinese Academy of Engineering and dean of Tsinghua University's Institute for Carbon Neutrality, emission reductions have been decisive. Preliminary analysis suggests local cuts accounted for more than half of the air quality improvement during the recent five-year plan period, while regional reductions contributed 30 to 40 percent, with their role increasing.

Weather conditions also played a part, he said, with favorable meteorology in 2025 contributing about 30 percent of the improvement, but he warned that this factor remains highly uncertain.

"Future weather could either help or pose greater challenges," he said, urging Beijing to rely on sustained emission reductions and higher-level technological support to offset climate variability.

City officials said the growing use of artificial intelligence and real-time monitoring, integrating satellite data, industrial sensors, vehicle tracking and construction surveillance, enable the identification of pollution sources with hour-level precision.

Echoing the emphasis on technology, Liu said Beijing has made major breakthroughs in precision pollution control by building an integrated air quality monitoring network linking satellite, ground-based and mobile data.

The system integrates satellite remote sensing, real-time industrial monitoring, dense ground-level sensors, power-use data and video surveillance from construction sites and vehicles across the city. Powered by AI, the platform enables precise source identification, dynamic tracking and early warning of pollution risks, allowing regulators to act in a targeted and efficient manner, Liu said.

Officials also highlighted parallel efforts to support cleaner transportation. In the past five years, Beijing has nearly doubled its number of public electric vehicle charging posts to 479,000, while battery swap stations increased to 360, according to Li Rugang, spokesman for the city's urban management commission.

Li said Beijing will focus on demand-driven optimization of energy infrastructure to support wider adoption of new energy vehicles and further improve the city's environmental livability.