Most Polluted Countries by PM2.5 (2023)
India was the world's most polluted country in 2023 with an average PM2.5 concentration of 79.9 µg/m³, about 16 times the WHO guideline of 5 µg/m³. Bangladesh and Tajikistan rounded out the top three.
Data
| # | Country | PM2.5 2023 | PM2.5 2022 | Change |
|---|---|---|---|---|
| 1 | India | 79.9 | 65.8 | +14.1 |
| 2 | Bangladesh | 73.7 | 70.9 | +2.8 |
| 3 | Tajikistan | 54.4 | 53.3 | +1.1 |
| 4 | Pakistan | 49.0 | 46.0 | +3.0 |
| 5 | Burkina Faso | 46.6 | 63.0 | -16.4 |
| 6 | Iraq | 43.8 | 80.1 | -36.3 |
| 7 | United Arab Emirates | 43.0 | 45.9 | -2.9 |
| 8 | Nepal | 42.4 | 40.1 | +2.3 |
| 9 | Egypt | 42.4 | 46.5 | -4.1 |
| 10 | Democratic Republic of the Congo | 40.8 | 15.5 | +25.3 |
| 11 | Kuwait | 39.9 | 55.8 | -15.9 |
| 12 | Bahrain | 39.2 | 66.6 | -27.4 |
| 13 | Qatar | 37.6 | 42.5 | -4.9 |
| 14 | Indonesia | 37.1 | 30.4 | +6.7 |
| 15 | Rwanda | 36.8 | 44.0 | -7.2 |
| 16 | Zimbabwe | 33.3 | -- | -- |
| 17 | Ghana | 33.2 | 30.2 | +3.0 |
| 18 | Kyrgyzstan | 33.1 | 31.1 | +2.0 |
| 19 | China | 32.5 | 30.6 | +1.9 |
| 20 | Libya | 30.4 | -- | -- |
| 21 | Laos | 29.6 | 27.6 | +2.0 |
| 22 | Vietnam | 29.6 | 27.2 | +2.4 |
| 23 | Uzbekistan | 28.6 | 33.5 | -4.9 |
| 24 | Gambia | 28.5 | -- | -- |
| 25 | Myanmar | 28.2 | 24.3 | +3.9 |
Note: The World's Most Polluted Countries in 2023, Measured by PM2.5
What PM2.5 Means
PM2.5 refers to fine airborne particles smaller than 2.5 micrometers in diameter, about 30 times thinner than a human hair. Because they are so small, they can bypass the body's natural defenses, travel deep into the lungs, and even enter the bloodstream. The World Health Organization sets a guideline of 5 µg/m³ as the annual average concentration considered safe; every country in this ranking exceeds that level many times over.
The 2023 Leaders
India was the most polluted country in the world in 2023, averaging 79.9 µg/m³ of PM2.5, roughly 16 times the WHO guideline and up 14.1 from 65.8 in 2022. Bangladesh followed at 73.7, with Tajikistan third at 54.4. Pakistan, Burkina Faso, Iraq, the United Arab Emirates, Nepal, Egypt, and the Democratic Republic of the Congo completed the top ten, all above 40 µg/m³.
- South Asia dominates the upper rankings, with India, Bangladesh, Pakistan, and Nepal all appearing in the top eight.
- China, often associated with smog, ranked 19th at 32.5 µg/m³, a sign of major air quality progress over the past decade.
- Iraq fell from 80.1 to 43.8 µg/m³, the largest improvement in the table at minus 36.3.
- The Democratic Republic of the Congo rose from 15.5 to 40.8 µg/m³, the largest year-on-year increase at plus 25.3.
Why Some Countries Are So Polluted
High PM2.5 levels tend to cluster where a combination of factors overlaps: dense traffic and older vehicles, coal and biomass burning for power and cooking, seasonal agricultural fires, dust storms, and rapid industrial growth without matching emission controls. In India, the winter months bring an infamous "smog season" when cooler air traps pollutants near the ground. In Gulf states like Iraq, Kuwait, Bahrain, and Qatar, desert dust blends with emissions from oil extraction and refineries. In West Africa, including Burkina Faso and Ghana, seasonal burning and Saharan dust are major contributors.
Health and Policy Impact
Long-term exposure to PM2.5 is linked to respiratory disease, heart disease, stroke, and lung cancer, and it is considered one of the largest environmental risk factors for premature death worldwide. Responses that have proven effective include emissions standards for vehicles and industry, cleaner cooking fuels, expanded public transit, and regional cooperation on agricultural burning and dust control.
Fun Facts
- India's 2023 average of 79.9 µg/m³ is about 16 times the WHO guideline of 5 µg/m³.
- Bangladesh was the only country besides India above 70 µg/m³, at 73.7.
- Iraq's improvement of 36.3 µg/m³ in one year is the biggest swing in the table, from 80.1 down to 43.8.
- Three Gulf states, Iraq, Kuwait, and Bahrain, all entered 2023 with levels above 55 µg/m³ the year before.
- Beijing-style smog is not unique to Asia; the Democratic Republic of the Congo's jump shows rapid urbanization can worsen air quality anywhere.
- Levels in the worst cities within these countries can be far higher than the national average, since national figures blend clean rural areas with polluted megacities.
- Zimbabwe, Libya, and Gambia had no comparable 2022 data in this table, so their change is shown as not available.
- Indonesia, at 37.1 µg/m³, regularly faces severe haze episodes caused by peat and forest fires, often during dry seasons.
