Several major cities around the world have achieved significant reductions in air pollution over the past decade, according to new analysis.

Cities including London, San Francisco and Beijing reduced levels of harmful pollutants by more than 20% since 2010. The improvements involve two key pollutants: fine particulate matter (PM2.5) and nitrogen dioxide (NO₂).

Researchers examined air quality data from nearly 100 cities worldwide. Their analysis identified 19 cities that achieved particularly strong improvements in pollution levels.

Meanwhile, experts say these results demonstrate that sustained policies and environmental reforms can significantly improve urban air quality within a relatively short period.

🚗 Transport Policies and Clean Energy Drive Improvements

Cities achieved these gains through targeted environmental policies and transportation reforms.

Many governments expanded cycle lanes, encouraged the use of electric vehicles, and introduced restrictions on high-polluting vehicles. These measures helped reduce emissions from transport, which remains one of the largest sources of urban air pollution.

For example, London implemented strict vehicle restrictions, while several European cities expanded cycling infrastructure to reduce car traffic.

Meanwhile, China accelerated the transition from petrol vehicles to electric cars, which significantly lowered emissions in large cities.

Experts say these policy decisions played a major role in improving air quality across urban areas.

📊 Beijing and Warsaw Lead Pollution Reduction Efforts

Among the cities analysed, Beijing and Warsaw achieved some of the largest improvements.

Both cities reduced levels of PM2.5 pollution by more than 45% over the period studied. This type of pollution contains microscopic particles that can enter the bloodstream and damage organs throughout the body.

Meanwhile, Amsterdam and Rotterdam recorded the largest reductions in nitrogen dioxide, cutting levels by more than 40%.

In the United States, San Francisco stood out as the only city to reduce both PM2.5 and nitrogen dioxide levels by more than 20%.

Overall, the analysis found that cities across Europe and Asia achieved most of the strongest improvements.

🧪 Experts Say Pollution Reduction Is Achievable

Environmental experts say the findings show that air pollution can be reduced through determined policy action.

Cecilia Vaca Jones, executive director of Breathe Cities, said the results demonstrate that cities now have the tools needed to tackle the problem.

“Cities can achieve what was once thought impossible,” she said, noting that some places cut toxic pollution by 20% to 45% in just over a decade.

Researchers emphasised that urban governments can achieve large improvements by combining multiple strategies, including cleaner transportation, energy reforms, and improved city planning.

⚠️ Air Pollution Still Poses Major Health Risks

Despite these improvements, experts warn that air pollution remains a major global health threat.

Pollutants such as PM2.5 and nitrogen dioxide can damage the lungs, heart, and other organs. Medical studies link exposure to conditions including asthma, cancer, heart disease, and cognitive decline.

Fine particulate matter is particularly dangerous because it can enter the bloodstream and circulate through the body.

Scientists say reducing these pollutants could save millions of lives globally each year.

🌱 Cities Demonstrate the Impact of Environmental Policies

Researchers say the findings highlight the power of long-term environmental policies.

Cities that implemented strong measures—such as electric vehicle adoption, clean energy policies, and traffic restrictions—achieved the most significant improvements.

Consequently, the analysis suggests that other urban areas could achieve similar results by adopting comparable strategies.

For now, experts say the success of these cities offers an important example of how governments can improve public health by reducing pollution.