Only 14% of global cities met WHO PM2.5 guideline in 2025, IQAir says

STEINACH, Switzerland, 26 March, 2026: IQAir said its 2025 World Air Quality Report shows a decline in global air quality, with only 14% of cities meeting the World Health Organization (WHO) annual PM2.5 guideline. IQAir said the findings are based on data from 9,446 cities across 143 countries, regions and territories, collected through more than 40,000 monitoring stations and sensors.

IQAir said only 13 countries, regions and territories globally recorded annual PM2.5 concentrations within the WHO guideline of five micrograms/m³. The organisation added that this represents a decline from 17% of cities meeting the guideline in 2024, highlighting a worsening trend in air quality performance.

IQAir said air pollution gained increased global attention in 2025, with international institutions elevating it as a major risk factor. The organisation added that the United Nations General Assembly classified air pollution as a significant contributor to non-communicable diseases, including cardiac disease, stroke and cancer.

IQAir said environmental factors, particularly wildfires, played a major role in degrading air quality during the year. The organisation added that biomass burning released approximately 1,380 megatonnes of carbon globally, contributing to elevated pollution levels.

According to IQAir, the highest population-weighted PM2.5 concentrations continued to be concentrated in Africa and Central and South Asia. The organisation added that countries including Pakistan, Bangladesh and India ranked among the most polluted globally based on annual averages.

IQAir said disparities in monitoring infrastructure remain a key challenge. The organisation added that Africa and West Asia continue to be underrepresented in monitoring networks, despite hosting some of the most polluted regions.

IQAir said non-government monitoring stations have become increasingly important in addressing data gaps. The organisation added that in many countries, such stations provided the only real-time air quality data available.

IQAir said PM2.5 remains the primary pollutant tracked in the report due to its significant health impacts. The organisation added that sources of PM2.5 include industrial emissions, transportation, power generation, agricultural burning and natural events, such as dust storms and wildfires.

IQAir said the findings highlight the need for sustained global efforts to improve air quality. The organisation added that maintaining clean air requires long-term strategies, continuous monitoring and coordinated action across governments and stakeholders.