Average PM2.5 levels in most polluted countries worldwide 2020-2021
Bangladesh had an average PM2.5 concentration of 76.9 micrograms per cubic meter of air (µg/m3) in 2021, making it the most polluted country in the world. This was almost 20 µg/m3 more than the average PM2.5 concentrations in India. The high levels of pollution in Bangladesh can be explained by the country's brick industry, which has thousands of coal-fired kilns pumping out harmful pollutants following a construction industry boom.
In 2020, many cities around the world experienced reductions in PM2.5 concentrations due to COVID-19 lockdowns and restrictions, with levels in Delhi falling roughly 15 percent compared with the previous year.
What are PM2.5 pollutants
PM2.5 refers to fine particles that have a diameter of 2.5 micrometers or less. These tiny, light, and inhalable pollutants can stay in the air for long periods of time and are a major risk to human health when concentrations are high. The World Health Organization advises that annual mean PM2.5 concentrations should not exceed 10 µg/m3. Major sources of PM2.5 include solid waste burning, road vehicles, and power plants.Pollution in cities
In 2021, Delhi was yet again the most polluted capital city in the world with an average PM2.5 concentration of 85 µg/m3. This was followed by the Bangladesh capital, Dhaka.In 2020, many cities around the world experienced reductions in PM2.5 concentrations due to COVID-19 lockdowns and restrictions, with levels in Delhi falling roughly 15 percent compared with the previous year.
