New Delhi has been ranked the world’s most polluted capital city for the second consecutive year. Delhi is followed by Dhaka (Bangladesh), N’Djamena (Chad), Dushanbe (Tajikistan), and Muscat (Oman).
12 of the 15 most polluted cities in Central and South Asia in 2021 were in India. New Delhi saw a 14.6 percent increase in PM2.5 concentration in 2021, 96.4 Ig/m3, up from 84 Ig/m3 in 2020.
The annual PM2.5 concentration averages in 48 percent of India’s cities, exceeded 50 Ig/m3 or more than 10 times the World Health Organization’s (WHO) air quality guidelines.
Crop burning is common in India, especially in the rice farms near Delhi during the winter months. During crop burning season, smoke is responsible for up to 45 percent of pollution in the city.
The 2021 World Air Quality Report states that only three percent of cities and no single country has met the latest WHO PM2.5 annual air quality guidelines.
The report analyses PM2.5 air pollution measurements from air monitoring stations in 6,475 cities in 117 countries, regions and territories.
IQAir’s 2021 World Air Quality Report is the first major global air quality report based on updated annual WHO air quality guidelines for PM2.5.
The new guidelines were released in September 2021 and cut existing annual PM2.5 guideline values from 10 Aug/m 3 to 5 Aug/m 3.
Fine particle pollution, known as PM2.5, is commonly accepted to be the most harmful, widely-monitored air pollutant and has been found to be a major contributing factor to health effects such as asthma, stroke, heart and lung diseases.