Only 14 per cent of cities worldwide breathe safe air, a drop from 17 per cent in the previous year.
Swiss pollution monitoring company IQAir analysed data from 9,446 cities in 143 countries, regions and territories, for its newly released 2025 World Air Quality Report.
It found air quality is deteriorating globally, largely due to human-caused climate change. Wildfire smoke, in particular, drove poor air quality in 2025, along with dust storms and other extreme weather events intensified by the burning of fossil fuels.
In the worst wildfire year on EU record, blazes swept across Europe, reaching their record-breaking peak in August when they lay ruin to farms, woodlands and homes. Extreme weather caused at least €43 billion in short-term economic losses across the continent, driven by deadly heatwaves, floods and droughts.
The WHO sets safe limits for PM2.5 or fine particulate matter due to their associated health risks. Their small size – less than 2.5 micrometres in diameter – mean these tiny, inhalable PM 2.5 particles can travel deep into the lungs and enter the bloodstream. They have been linked to respiratory issues, cardiovascular diseases, and long-term illnesses like cancer.
Only three European countries now fall within safe guidelines.
Where in Europe has the best and worst air quality?
In Europe, Andorra, Estonia and Iceland are the only countries that met the WHO annual PM2.5 guideline – 5 micrograms per cubic metre (µg/m³) – in 2025.
They’re among just 13 countries and territories globally that remained within safe limits. The others included Australia, Barbados, Bermuda, French Polynesia, Grenada, New Caledonia, Panama, Puerto Rico, Réunion, and the US Virgin Islands.
That means 130 of the 143 countries covered – or 91 per cent – did not meet safe guidelines.
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).
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 – including the unenviable number one.
Loni in the northern state of Uttar Pradesh had an annual average PM2.5 concentration of 112.5 µg/m³ – nearly 23 per cent higher than in 2024 and more than 22 times the WHO guideline. A 2024 survey showed traffic, industrial emissions, road dust and fly tipping to be the biggest sources of pollution.
Nieuwoudtville, South Africa, was the least polluted place on the list, with an annual average PM2.5 concentration of 1.0 µg/m³. Part of the vast and rugged terrain of the Namaqualand region of the Karoo, Nieuwoudtville is a favourite with flower enthusiasts thanks to its annual bloom.
Where has the worst air pollution in Europe?
Across Europe in 2025, 23 countries recorded increases in annual average PM2.5 concentrations, 18 recorded decreases, and one was newly added.
PM2.5 pollution rose by more than 30 per cent in Switzerland and Greece due to wildfire smoke from North American and Saharan dust from Africa. Malta recorded the largest decrease at nearly 24 per cent. This is partly thanks to long-standing efforts to shift its energy generation away from heavy fuel oil and towards renewables, as well as policies targeting traffic emissions.
IQAir also features live rankings, which use real-time air quality monitoring. At the time of writing, Paris was in the top five most polluted cities globally, alongside Beijing, Dhaka, Wuhan and Seoul. London was also in the top 10.
Last Thursday (19 March), the EU’s Copernicus Atmosphere Monitoring Service (CAMS) warned of high PM2.5 pollution levels in Europe, driven by seasonal agricultural ammonia emissions from fertiliser, rises in certain pollen concentrations, and stagnant weather conditions.
Background pollution from fossil fuel combustion – especially across parts of Eastern Europe and the Balkans – also consistently contributes to poor air quality, Copernicus said.
Germany, France, the Netherlands, Belgium, the UK, and Ireland were among the countries expected to be impacted over the coming days.
Air quality data gaps remain
While 54 countries experienced increases in annual average PM2.5 in the new World Air Quality Report, 75 saw reductions and two remained unchanged.
Although this year’s report includes 12 additional countries that did not feature last year, major data gaps remain. According to IQAir, only a fraction of the global population have access to hyper-local, real-time air quality information.
And in some places, it’s getting worse. In March 2025, the Trump administrationscrapped the US State Department’s global air quality monitoring program, leaving millions without access to data.
The Finland-based Centre for Research on Energy and Clean Air (CREA) reported monitoring efforts in 44 countries were weakened and six were left without any monitoring.
“Without monitoring, we cannot fully understand what’s in the air we breathe,” says IQAir Global CEO Frank Hammes. “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.”
SOURCE: EURONEWS
