Chad and Bangladesh  ranked as the most polluted countries in 2024, while Delhi, India was the most polluted capital city, according to the 2024 World Air Quality report produced by the Swiss-based IQAir.  But only seven countries worldwide met WHO air quality guidelines and Africa’s pollution levels remains under-reported. Pollution monitoring also fell victim to President Trump drastic cuts and rollbacks of environmental protections, as US embassies worldwide closed monitoring stations and disabled the US government’s airnow.gov data base.

Seventy-four of the 100 most polluted cities and towns are in India, according to the latest World Air Quality Report 2024, a slight improvement from 83 last year. Levels of a key microscopic pollutant, PM2.5,  declined 7% across the nation, averaging 50.6 micrograms/cubic metre or 10 times the World Health Organization’s (WHO) safe guideline.  Despite having the most polluted cities, India ranked fifth, globally, after Chad, Bangladesh, Pakistan, and the Democratic Republic of Congo in terms of national pollution levels.

Globally, only 17% of the almost 9,000 cities surveyed met the WHO air pollution standard, which is an annual average of 5 micrograms/cubic metre of the pollutant PM 2.5. This microscopic particulate matter, containing a cocktail of other pollutants that penetrate the blood and brain barrier, is the most widely tracked measure of air pollution.  Nationally, only seven countries: Australia, New Zealand, the Bahamas, Barbados, Grenada, Estonia and Iceland met WHO annual air quality levels, IQAir said.