China marks this year's International Day of Clean Air for blue skies after recording its best annual air quality since national monitoring began. The gains reflect concerted efforts to curb pollution through cleaner energy, industrial upgrades and greener transport. Tighter national standards now set the benchmark for sustaining that progress.

Between 2021 and 2025, China's average PM2.5 concentration fell by 20% while its gross domestic product grew by about 30%. The contrast speaks to a question confronting industrial economies around the world: Can production and mobility continue to grow without worsening air pollution?

China's latest figures suggest progress is possible. During the first half of 2026, the average PM2.5 concentration across 339 cities at or above prefecture level was 29.9 micrograms per cubic meter, down 6.6% from a year earlier, according to the Ministry of Ecology and Environment.

The proportion of days with good or excellent air quality rose to 82.8%, from 78.3% a year earlier. In 2025, the full-year figure reached a record 89.3%, while average PM2.5 fell to 28 micrograms per cubic meter.

Behind those numbers is a shift from treating pollution after it is produced to reducing emissions throughout the economy.

Heavy industry has been a main front. By the end of 2025, China had completed ultra-low-emission upgrades covering 940 million tonnes of crude steel production capacity and 170 gigawatts of coal-fired power capacity. China also carried out extensive upgrades in the coking and cement industries.

The retrofits are designed to cut pollutants including dust, sulfur dioxide and nitrogen oxides. Combined with the retirement of outdated production capacity, they make air-quality improvement part of industrial modernization rather than a separate environmental measure.

Transport represents another distinctly Chinese part of the transition.

By the end of 2025, China had 43.97 million new energy vehicles, up 12.57 million in one year. The category includes battery-electric cars, plug-in hybrids and fuel-cell vehicles. Electric cars, buses, and delivery vehicles can reduce exhaust pollution, particularly in large cities where traffic is a major source of local emissions.

However, their broader environmental impact depends partly on how their electricity is produced. This makes transport electrification inseparable from changes in the power system.

Solar power overtook coal in July to become China's largest source of installed generating capacity. But coal still produced 49.7% of the country's electricity in the first half of 2026. The gap between capacity and actual generation highlights the need for more energy storage, stronger transmission networks and a more flexible grid.

Technology within individual cities is also not enough. Air pollution crosses administrative boundaries, making regional cooperation essential.

From 2021 to 2025, PM2.5 concentrations fell by 27.7% in the Beijing-Tianjin-Hebei region and surrounding areas and by 32.1% in the Fenwei Plain, both faster than the national average. The regional response has included joint monitoring, forecasting and enforcement, treating pollution as a cross-border problem rather than a collection of isolated local ones.

Progress is nevertheless uneven. July data showed declines in both PM2.5 and ozone in the Yangtze River Delta, while ozone increased in the Fenwei Plain. This difference shows why further improvements will require more targeted controls and greater attention to pollutants beyond PM2.5.

China has also raised the regulatory bar. New national standards introduced in March lowered the transitional annual PM2.5 limit from 35 to 30 micrograms per cubic meter through 2030. A tighter limit of 25 micrograms is set to follow.

This broader approach echoes a new assessment released by the United Nations Environment Programme for the International Day of Clean Air for blue skies. It argues that clean-air and climate policies deliver greater benefits when designed together because many of the same sectors, including industry, transport and energy, drive both problems.

China provides a large-scale example of that approach, as well as an unfinished test. The first stage of its campaign made blue skies more common. The next stage will focus on keeping the air clean as energy demand, industrial production and urban mobility continue to grow.