China on Tuesday released a new round of revisions to further strengthen its ambient air quality standards, building on the overall improvements in air quality seen in recent years.

Under the new standards released by the Ministry of Ecology and Environment, the annual average limit for PM2.5 will be tightened from 35 to 25 micrograms per cubic meter. The annual limit for PM10 will be reduced from 70 to 50 micrograms per cubic meter.

The annual limit for sulfur dioxide will drop from 60 to 20 micrograms per cubic meter, while the limit for nitrogen dioxide will drop from 40 to 30 micrograms per cubic meter.

Relevant monitoring methods and technical specifications have also been updated.

The new standards will be implemented in two phases to ensure a smooth transition. Transitional limits will be applied from March 1 this year through December 31, 2030, setting the annual PM2.5 limit at 30 micrograms per cubic meter and the PM10 limit at 60 micrograms per cubic meter.

Starting January 1, 2031, the revised limits for PM2.5, PM10, sulfur dioxide and nitrogen dioxide will take full effect nationwide.

China's air quality has improved considerably over the past few years. For instance, local environmental authorities announced last month that the capital, Beijing, experienced just one day of heavily polluted air in 2025, a staggering reduction from 58 such days in 2013, marking a major victory in the city's battle against air pollution.