According to the 2020 list compiled by the UChicago ACLI and referenced in the Wikipedia list of countries by air pollution, India had the highest level of particulate matter (PM2.5), indicating the dirtiest air among the ranked countries in that specific list.
Air Quality Rankings (2020 List)
Air pollution is often measured by the concentration of fine particulate matter, known as PM2.5. These tiny particles, less than 2.5 micrometers in diameter, can penetrate deep into the lungs and bloodstream, posing significant health risks.
The provided data from the 2020 UChicago ACLI list shows the following countries with the highest average PM2.5 concentrations:
| Rank | Country | Particulate Matter (PM2.5) (in µg/m³) |
|---|---|---|
| 1 | India | 75.76 |
| 2 | Pakistan | 55.80 |
| 3 | Nepal | 47.13 |
| 4 | Bangladesh | 44.17 |
For comparison, the World Health Organization (WHO) Guideline for annual average PM2.5 concentration is 5 µg/m³. The levels listed above are significantly higher than this recommended guideline.
Understanding PM2.5
- Source: PM2.5 particles come from various sources, including vehicle emissions, industrial processes, power plants, residential heating, agricultural burning, and natural sources like dust storms.
- Health Impact: Exposure to high levels of PM2.5 is linked to respiratory illnesses, heart disease, stroke, lung cancer, and other severe health problems.
- Measurement: Concentrations are typically measured in micrograms per cubic meter (µg/m³).
The ranking reflects the average annual concentration across the country for the year the data represents (2020 in this case). Air quality can vary significantly within a country depending on urbanisation, industrial activity, geographical factors, and weather patterns.
