If you've visited Beijing, London, or Paris in recent years and noticed the air felt a little cleaner, you weren't imagining it. A new report from Breathe Cities has confirmed what residents of these metropolises have been sensing: the air is genuinely, measurably better.
The Breathe Better Report, released this week, identifies 19 major cities across the globe that have achieved remarkable reductions in air pollution — cutting levels of fine particulate matter (PM2.5) and nitrogen dioxide (NO₂) by between 20 and 45 percent over the past 15 years.
Beijing and Warsaw Lead the Charge
Beijing and Warsaw emerged as the standout performers for PM2.5 reduction, both slashing levels by more than 45 percent. For Beijing — a city once synonymous with smog so thick it obscured skyscrapers — the transformation has been nothing short of extraordinary. A combination of strict emissions standards, industrial relocation, and massive investment in public transit and electric vehicles has fundamentally changed the city's air.
Meanwhile, Amsterdam and Rotterdam recorded the greatest improvements in nitrogen dioxide levels, with cuts exceeding 40 percent. The Dutch cities' aggressive cycling infrastructure and early adoption of low-emission zones have paid measurable dividends.
The Global Picture
The 19 cities identified in the report span four continents: Brussels; Beijing, Chengdu, Hangzhou, Hong Kong, Nanjing, Qingdao, Shenzhen, Wuhan, and Zhenjiang in China; Paris; Berlin and Heidelberg; Rome; Amsterdam and Rotterdam; Warsaw; London; and San Francisco.
Nearly half of the cities on the list are in Asia, where air quality improvements came despite rapid economic growth — demolishing the old assumption that development and clean air are incompatible. Nine of the 19 are Chinese cities, reflecting the country's enormous investments in renewable energy, electric buses, and industrial modernization.
What Worked
The report identifies several common strategies among the successful cities. Cycling infrastructure investment was a major factor, with cities like Amsterdam, Paris, and Beijing all dramatically expanding bike lanes and bike-sharing programs. Clean air zones — areas where the most polluting vehicles face restrictions or fees — proved highly effective in European cities. And the switch to electric vehicles, particularly in public transit fleets, delivered measurable improvements across the board.
"The pathway to cleaner air has been tested at scale — now it's about enabling more cities to follow it," said Cecilia Vaca Jones, Breathe Cities' executive director.
The Work Isn't Done
The report comes alongside a sobering reminder from IQAir's 2025 World Air Quality Report: only 14 percent of cities worldwide currently meet the World Health Organization's pollution guidelines. Air pollution remains the world's leading environmental health risk, driving respiratory disease, cardiovascular problems, asthma, and premature births, with lower-income communities bearing the heaviest burden.
But the Breathe Cities findings prove that dramatic improvement is possible within a single generation. For the 19 cities on the list, cleaner air isn't a distant aspiration — it's an accomplished fact. The question now is how quickly the rest of the world can follow their lead.
