The World's Most and Least Polluted Cities

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 of the most polluted cities in the world is the most polluted, we had to use credible and validated sources. For this reason, we decided to use IQAir’s 2023 air quality data, which measures the annual average of PM 2.5 concentration (µg/m³).

World’s Most Polluted Cities 2023

The top ten list of the world's most polluted cities as of 2023 is:

1. Begursarai, India – 118.9 μg/m³

2. Guwahati, India – 105.4 µg/m³

3. Delhi, India– 102.1 µg/m³

4. Mullanpur, India– 100.4 µg/m³

5. Lahore, Pakistan – 99.5 µg/m³

6. New Delhi, India – 92.7 µg/m³

7. Siwan, India – 90.6 µg/m³

8. Saharsa, India – 89.4 µg/m³

9. Goshaingaon, India – 89.3 µg/m³

10. Katihar, India – 88.8 µg/m³

Despite Bangladesh being the most polluted country in the world in 2023, 90% of the world’s top 10 most polluted cities are in India, with Begursarai taking the top spot. In fact, 84% of the top 50 most polluted cities in the world are in India, meaning that over 1.190 billion people in India are breathing dangerously unsafe air.

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 2.18 millions premature deaths in the country each year while the whole world premature deaths are estimated to be 8.34 million people.

This is the first time the city of Begursarai has risen to the top of the list as the PM2.5 concentration (μg/m³) went from 19.7 μg/m³ in 2022 to 118.9 μg/m³ in 2023, registering the highest increase in PN2.5 concentration between 2022 and 2023. In 2022, the top spot belonged to the city of Mullanpur in India, which had an average PM2.5 concentration of 185.5 μg/m³, but has since improved its concentration levels to an average of 78.1 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 Mullanpur in India, which saw a 85.1 µg/m³ drop from 185.5 µg/m³ in 2022 to 100.4 µg/m³ in 2023 despite being the 4thmost pollute city in the world.

Despite some improvements in the chart, all of the top 132 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.

However, the situation could be much worse than what was reported above due to missing data.

Regarding countries, please note that in 2023, countries, regions, and territories in Africa and Central and South Asia experienced the highest annual average PM2.5 concentrations when weighted by population. Although air quality data availability in Africa is gradually increasing, only 24 out of 54 African countries had sufficient data to be included in the 2023 report, leaving 30 countries without representation.

Afghanistan, which consistently ranked among the top 15 most polluted countries since 2019, and Oman, ranked as the 6th most polluted country in 2022, are notably absent due to insufficient data. In 2023, 20 new countries were represented, including Burkina Faso, the 5th most polluted country, and Rwanda, the 15th most polluted country of the year. Additionally, 10 countries, territories, and regions, many located in Oceania, met the WHO's annual PM2.5 guideline in 2023.

World’s Least Polluted Cities in 2023

The top ten list of the world's least polluted cities as of 2023 is:

1. Zurich, Switzerland – 0.4 μg/m³

2. Perth, Australia – 1.5 µg/m³

3. Hobart, Australia – 2.3 µg/m³

4. Uppsala, Sweden – 3.5 µg/m³

5. Launceston, Australia – 3.5 µg/m³

6. Reykjavik, Iceland – 4.0 µg/m³

7. Tampere, Finland – 4.0 µg/m³

8. Turku, Finland – 4.1 µg/m³

9. Vancouver, Canada – 4.3 µg/m³

10. Wollongong, Australia – 4.4 µg/m³

Although Australia was the 7th least polluted country, 40% of the top 10 least polluted cities are in Australia. This is mainly due to how remote the cities in this list are. But with increased urbanisation across the country and a growing population, which is resulting in increased energy consumption and transport, the country is far from hitting perfect scores when it comes to air quality.

How to Quickly Reduce Pollution Levels in the World’s Most Polluted Cities

When it comes to reducing pollution levels, there are no silver bullets or easy fixes, but with collective actions and government schemes, it’s possible to reduce the levels to improve the air quality.

Globally, governments are introducing schemes to reduce air pollution in cities. These include clean air zones, congestion charges, banning the most polluting vehicles, reclaiming road space for trees and green spaces and innovative technologies that scan the air for pollution.

If action isn't taken now, we'll likely see air pollution levels continue to rise each year. Now is the time to make a change.

Reduce Air Pollution in Your Community with Pure Air Zone

If you’re feeling a bit helpless after reading this, there are a few ways you can make a direct impact on air quality within your community and beyond.

Pure Air Zones is a concept developed by U-Earth that allows businesses to offer clean air to their customers, visitors, clients and employees. The more Pure Air Zones there are, the more impact on air pollution they’ll have.

If you’re a business, you can book a meeting with one of our air quality specialists to see how you and your company can make a difference today. If you’re an individual, you can prompt your favourite businesses (or any business at all!) to become a Pure Air Zone through the Pure Air Zone App or join our newsletter below to stay informed on how you can help.

Happy air purifying!