Pakistan was ranked the most polluted country in the world in 2025, according to the latest air quality report from Swiss monitoring firm IQAir. Concentrations of fine particulate matter (PM2.5) in Pakistan reached up to 13 times the World Health Organization (WHO) recommended limit.
The annual report found that 130 out of 143 monitored countries and territories failed to meet the WHO guideline of less than 5 micrograms per cubic metre of PM2.5. Bangladesh and Tajikistan followed Pakistan as the second and third most polluted nations, while Chad, the most polluted country in 2024, dropped to fourth—though IQAir noted gaps in data may have affected the ranking.
City-level data showed India’s Loni as the most polluted city globally, averaging 112.5 micrograms of PM2.5 per cubic metre, with Hotan in China’s Xinjiang region close behind at 109.6 micrograms. All of the world’s top 25 most polluted cities were located in India, Pakistan, or China.
Greece’s Air Quality Still Above WHO Guidelines
While Greece does not rank among the most polluted nations globally, recent air quality data show PM2.5 levels there remain elevated relative to WHO targets. The country’s average annual PM2.5 concentration was about 11.53 µg/m³ in 2024, roughly 2.3 times the WHO guideline value , placing it in 67th place.
Real‑time monitoring across Greek cities highlights periodic spikes in pollution. Cities such as Larisa, Volos, Athens and Chania have recorded moderate to unhealthy air quality index (AQI) levels at times, indicating localized smog conditions that can affect public health .
Ioannina, in the Epirus region, has been noted as one of Greece’s most polluted areas, along with industrial and urban zones in Thessaloniki, Kozani, and Attica, often linked to emissions from traffic, heating, and industry .
Only a small portion of Greek cities consistently show lower AQI values, with cleaner readings reported in some coastal and less industrialized towns.
Globally
Globally, only 14% of cities met WHO air quality standards in 2025, a decline from 17% in 2024. Researchers highlighted that Canadian wildfires contributed to elevated PM2.5 levels across the United States and even parts of Europe.
On a positive note, some countries saw improvements: Laos, Cambodia, and Indonesia recorded notable reductions in PM2.5 due to wetter and windier La Niña conditions, while Mongolia’s average levels fell by 31% to 17.8 micrograms per cubic metre. Australia, Iceland, Estonia, and Panama were among the few countries meeting WHO air quality standards in 2025.
The report also noted that U.S. budget cuts led to the closure of a global monitoring program in March 2025, which had collected pollution data from embassies and consulates. This affected the availability of reliable data for several smog-prone countries, including Burundi, Turkmenistan, and Togo.
Overall, 75 countries reported lower PM2.5 levels in 2025 compared to the previous year, while 54 countries recorded higher averages, reflecting ongoing global challenges in managing air pollution.
