These Are The Most-Polluted Countries In The World

Almost the entire global population breathes air that exceeds the air quality limits set by the World Health Organization (WHO).

In this graphic, Visual Capitalist's Marcus Lu maps the world’s most polluted countries according to IQAir, ranked by their annual average PM2.5 concentration (μg/m³) in 2023. The unit μg/m³ refers to micrograms per cubic meter.

What is PM2.5?

PM2.5 refers to fine particulate matter, with a diameter of 2.5 micrometers or less, that can travel deep into your lungs and cause health problems.

In 2021, the World Health Organization (WHO) updated its air quality guidelines for PM2.5. The recommended maximum annual average level for PM2.5 is now 5 μg/m³, down from the previous target of 10 μg/m³.

Common sources of PM2.5 pollution include engine exhaust, power plant combustion, smoke from fires, dust, and dirt.

How Does PM2.5 Pollution Affect Humans?

Research published in 2022 from the Air Quality Life Index (AQLI) found that 97.3% of the world’s population is exposed to levels of PM2.5 that exceed the WHO guidelines.

This takes 2.2 years off the global average life expectancy, relative to a world that met the WHO guideline.

In South Asia specifically, the AQLI believes residents could be losing up to 5 years off their lives. The region has been a global hotspot of air pollution for years, home to 37 of the 40 most polluted cities in the world.

Interestingly, fine particulate matter can travel hundreds of kilometers, often crossing national boundaries.

For instance, approximately 30% of air pollution in the Indian state of Punjab originates from neighboring Pakistan. Similarly, an estimated 30% of pollution in Bangladesh’s largest cities is traced back to India.