Most polluted countries based on PM2.5 concentration globally 2022
Chad had an average PM2.5 concentration of nearly 90 micrograms per cubic meter of air (µg/m3) in 2022, becoming the most polluted country in the world. This was roughly 35 µg/m³ more than the average PM2.5 concentration in India. The high levels of pollution in Chad can be explained by the country's oil, textile and meatpacking industries, in addition to vehicle emissions and waste burning.
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 5 µg/m³. Major sources of PM2.5 include solid waste burning, road vehicles, and power plants.
Pollution in cities
In 2022, N’Djamena was the most polluted capital city in the world, with an average PM2.5 concentration of 89.7 µg/m³. This was followed by the Indian capital, New Delhi. Despite these high PM2.5 levels, the most polluted city worldwide was Lahore – in northeastern Pakistan – with an average PM2.5 concentration of 97.4 µg/m³.