Cities Prove Clean Air Is Possible: 19 Cut Pollution by More Than 20%
Research highlighted by the Clean Air Fund found that 19 cities worldwide cut levels of key air pollutants by more than 20%, with London, San Francisco and Beijing among those showing notable long-term declines in particulate matter and nitrogen oxides. The findings show that ambitious, multi-sector policies can deliver lasting clean-air gains.
EnvironmentGNGV Editorial Team5 min read
Air pollution is the world's leading environmental health risk, linked to millions of premature deaths each year, so progress on it touches lives directly. While global air quality faced setbacks in 2025 — driven heavily by record wildfire smoke — there is an encouraging counter-story playing out in cities that have chosen to act. Research highlighted by the Clean Air Fund in March 2026 found that 19 cities around the world cut levels of key pollutants by more than 20%.
Among the standouts, London, San Francisco and Beijing have all seen notable drops in particulate matter and nitrogen oxide pollution over the past decade. These are not abstract statistics; they reflect deliberate choices. London expanded low-emission zones that charge or restrict the most polluting vehicles. Beijing tightened industrial controls and shifted away from coal heating. San Francisco and other cities invested in cleaner transport and tougher emissions standards. The lesson, as the research frames it, is that "ambitious, multi-sectoral policies can deliver sustained improvements."
The broader context is sobering and important to state plainly. According to global monitoring, only a small fraction of cities currently meet the World Health Organization's guideline for safe air, and 2025 saw global air quality worsen overall, partly because intensifying wildfires released enormous quantities of smoke across Europe and North America. Climate change and air pollution are deeply intertwined, and the wildfire problem underscores how hard-won local gains can be undercut by warming-driven disasters.
But the city-level successes carry a clear and hopeful message: clean air is achievable with the right policies, and the benefits are immediate. Unlike many climate measures whose payoff lies decades away, cutting urban air pollution improves public health almost at once — fewer asthma attacks, fewer heart and lung problems, longer lives. The 19 cities cutting pollution by a fifth or more show that this is not a distant aspiration but a present-day result, achieved by ordinary policy tools applied with determination. They offer a template that hundreds of other cities can follow.
