The World's Most and Least Polluted Cities
Updated: Sep 8, 2022
According to the United Nations, almost two thirds (57%) of the world lives in cities. Urban areas see higher levels of pollution meaning billions of people are living in areas with unsafe air. Despite this, there are many cities in the world that are demonstrating how urban areas can live with cleaner air. Here you’ll find out what they are and what’s causing the most and least polluted cities.
Measuring the World’s Most Polluted Cities
To find out which are the most polluted cities in the world, we had to use a credible and validated source. For this reason, we decided to use IQAir’s 2021 air quality data, which measures the annual average of PM 2.5 concentration (µg/m³).
World’s Most Polluted Cities
The top ten list of the world's most polluted cities as of 2021 is:
Bhiwadi, India – 106.2 μg/m³
Ghaziabad, India – 102 µg/m³
Hotan, China – 101.5 µg/m³
Delhi, India– 96.4 µg/m³
Jaunpur, India – 95.3 µg/m³
Faisalabad, Pakistan – 94.2 µg/m³
Noida, India – 91.4 µg/m³
Bahawalpur, Pakistan – 91 µg/m³
Peshawar, Pakistan – 89.6 µg/m³
Bagpat, India – 89.1 µg/m³
Despite Bangladesh being the most polluted country in the world in 2021, 60% of the world’s top 10 most polluted cities are in India, with Bhiwadi taking the top spot. In fact, 70% of the top 50 most polluted cities in the world are in India, meaning that over 140 million people in India are breathing unsafe air. Cities in Pakistan, China, Bangladesh, Chad, Kazakhstan and Turkey fill the other 30%.
The combination of coal-fired power plants, factories, biomass burning and millions of vehicles are the main causes of smoke, smog and particulate pollution in India. This leads to over 2 millions premature deaths in the country each year.
This is the first time the city of Bhiwadi has risen to the top of the list as the PM2.5 concentration (μg/m³) went from 95.5 μg/m³ in 2020 to 106.2 μg/m³ in 2021. In 2020, the top spot belonged to the city of Hotan in China, which had an average PM2.5 concentration of 110.2 μg/m³, but has since improved its concentration levels to an average of 101.5 μg/m³.
The biggest increase in PM.25 concentration was from the city of Faisalabad in Pakistan, which went from 73.2 µg/m³ in 2020 to 94.2 µg/m³ in 2021, an increase of 21 µg/m³. However, many of the most polluted cities have seen improvements to their air pollution levels over the last few years, with the largest decrease going to Ghaziabad in India, which saw a 42.6 µg/m³ drop from 144.6 µg/m³ in 2017 to 102 µg/m³ in 2021.
Despite some improvements in the chart, all but one of the top 40 most polluted cities exceed the WHO air quality limit by over 10 times. This is a seriously worrying stat considering these cities house millions of people, all of which are affected by the air quality that they’re living in, and that we’re facing a climate crisis, which needs more drastic change if we’re to continue inhabiting a safe planet.
World’s Least Polluted Cities
The top ten list of the world's least polluted cities as of 2021 is:
Shu, Kazakhstan – 1.5 μg/m³
St. Helens, Australia – 1.9 µg/m³
Judbury, Australia – 2 µg/m³
Mornington, Australia – 2.4 µg/m³
Gretna, Australia – 2.6 µg/m³
Derby, Australia – 2.6 µg/m³