IQAir's 2025 World Air Quality Report Finds Only 14% of Cities Meet WHO Air Pollution Guideline

New data shows global air quality progress stalling as wildfire smoke and climate change intensify global air pollution. Despite some regional improvements, major data gaps remain, with only a fraction of the global population having access to hyper-local, real-time air quality information.

STEINACH, Switzerland, March 24, 2026 /PRNewswire/ -- IQAir today announced the release of its 8th annual World Air Quality Report, offering a comprehensive analysis of 2025 global air pollution data and highlighting persistent health risks, emerging regional trends and critical monitoring gaps worldwide.

For this year's report, IQAir analyzed data from monitoring stations across 9,446 cities in 143 countries, regions and territories. The report adds 12 countries and territories not included last year, seven of which appear in the dataset for the very first time, marking continued expansion of global air quality monitoring coverage.

Comparing this year's report to the previous year, 54 countries experienced increases in annual average PM2.5, 75 saw reductions and two remained unchanged.

Key findings from the 2025 World Air Quality Report:

• Only 14% of global cities met the World Health Organization (WHO) annual PM2.5 guideline of 5 µg/m³, down from 17% the previous year.
  
  
• Only thirteen countries and territories met the WHO annual PM2.5 guideline: French Polynesia, Puerto Rico, U.S. Virgin Islands, Barbados, New Caledonia, Iceland, Bermuda, Réunion, Andorra, Australia, Grenada, Panama and Estonia.
  
  
• 130 out of 143 countries, regions and territories (91%) did not meet the WHO annual PM2.5 guideline value.
  
  
• The five most polluted countries were Pakistan (67.3 µg/m³), Bangladesh (66.1 µg/m³), Tajikistan (57.3 µg/m³), Chad (53.6 µg/m³) and the Democratic Republic of the Congo (50.2 µg/m³).
  
  
• Loni, India, was the most polluted city, recording an annual average PM2.5 concentration of 112.5 µg/m³ - a nearly 23% increase from 2024 and more than 22 times the WHO guideline.
  
  
• Nieuwoudtville, South Africa, was the world's cleanest city, with an annual average PM2.5 concentration of 1.0 µg/m³.
  
  
• The world's 25 most polluted cities were all located in India, Pakistan and China, with India home to three of the four most polluted.
  
  
• The most polluted major U.S. city was El Paso, Texas. Southeast Los Angeles, California was the most polluted region in the United States. Seattle, Washington was the cleanest major U.S. city.
  
  
• 2025 marked the second consecutive year in which no cities in East Asia met the WHO PM2.5 guideline. Pollution patterns in China indicate a westward shift in elevated concentrations.
  
  
• Europe saw mixed air pollution trends in 2025, with 23 countries recording higher PM2.5 concentrations and 18 seeing declines, while winter wood burning, summer transboundary smoke from Canadian wildfires and Saharan dust worsened seasonal pollution.
  
  
• In Latin America and the Caribbean, air quality trends were largely positive: 208 cities recorded decreases in annual PM2.5 concentrations, 95 increased and nine remained unchanged.
  
  
• Oceania remained one of the world's cleanest regions with 61% of cities meeting the WHO guideline, though record-breaking cold in New South Wales, Australia in June 2025 led to seasonal PM2.5 spikes.

Wildfires, intensified by climate change, played a major role in degrading global air quality in 2025. Record wildfire biomass emissions from Europe and Canada contributed to approximately 1,380 megatons of carbon being released. In Northern America, Canada was more polluted than the United States for only the second time in this report's eight-year history, as its second-worst wildfire season on record affected air quality across Canada, the United States and parts of Europe.

In the United States, annual average PM2.5 levels increased to 7.3 µg/m³, compared to 7.1 µg/ m³ the previous year. Smoke from wildfires in both Canada and the U.S. raised averages across parts of the Great Lakes states in the summer and in the Pacific Northwest in the fall.

El Paso was the most polluted major city in the United States. Historic dust storms triggered a 46% increase in average PM2.5 levels to 11.4 µg/m³ as the city recorded the highest number of major pre-summer dust storms since the 1930s. The Southeast Los Angeles region (Cudahy, East Los Angeles, Huntington Park), heavily impacted by wildland-urban interface fires, ranked as the most polluted area in the country. Seattle remained the cleanest major U.S. city for the second consecutive year, with an annual average of 4.5 µg/m³.

Across Europe, 23 countries recorded increases in annual average PM2.5 concentrations, 18 recorded decreases, and one was newly added. Switzerland and Greece experienced increases exceeding 30% due to transboundary wildfire smoke from Northern America and Saharan dust from Africa. Malta recorded the largest decrease at nearly 24%.

The end of the United States State Department's global air quality monitoring program at embassies and consulates in March 2025 caused millions to lose access to this trusted air quality data. The Centre for Research on Energy and Clean Air (CREA) reported monitoring efforts in 44 countries were weakened and six were left without any monitoring.

"Air quality is a fragile asset that requires active stewardship to protect public health," says IQAir Global CEO Frank Hammes. "The 2025 World Air Quality Report makes clear that without monitoring, we cannot fully understand what's in the air we breathe. Expanding access to real-time data empowers communities to act. By reducing emissions and addressing climate change, we can drive meaningful, lasting improvements in global air quality."

The 2025 report underscores the importance of expanding air quality monitoring networks, particularly through low-cost sensors that empower communities, researchers and policymakers with actionable data.

"The World Air Quality Report reveals two competing realities: an air pollution crisis and the rise of communities, scientists and data working to meet the challenge," states Dr. Aidan Farrow, Senior Scientist, Greenpeace International. "In 2025, familiar culprits like industrial agriculture, wildfires and fossil fuels left their mark in the data collated by IQAir worldwide. This open, transparent data is an essential tool for holding polluters accountable and securing a healthy environment for everyone."

IQAir's 2025 World Air Quality Report serves as a global benchmark to understand air pollution exposure, inform policy decisions and accelerate collective efforts toward cleaner air worldwide.

To download the 2025 World Air Quality Report, CLICK HERE.

To watch IQAir's video "Understanding IQAir's 2025 World Air Quality Report: A Global View," CLICK HERE.

About IQAir:

IQAir is a Swiss technology company that empowers individuals, organizations, and governments to improve air quality through information, collaboration, and intervention. 

Media contact:

Armen Araradian
[email protected]
+1 (562) 252-8224

SOURCE IQAir