5 Most polluted major cities in the world in 2024

The 2024 World Air Quality Report is out. It reveals ongoing, alarming levels of pollution in many major cities worldwide.

Urban residents face heightened air pollution challenges due to higher concentration of pollutants, weak regulatory enforcement, overburdened infrastructure, and rapidly growing populations. For people living in the five most polluted cities, unhealthy air exposure was an almost daily reality in 2024. Several of these cities have consistently ranked among the most polluted globally year after year.

“More than 96 million people reside in the five most polluted cities in the world.”

More than 96 million people reside in the five most polluted cities in the world. Millions more endured frequent exposure to poor air quality throughout 2024.

5. Karachi, Pakistan

Karachi, the largest city in Pakistan, grapples with significant air quality issues. In 2024, the city’s average annual PM2.5 concentration was 47.1 µg/m³. After five years of increasingly worsening air quality, this does represent an improvement air quality over previous years. In 2023, the average annual PM2.5 concentration was 56.1 µg/m³. However, 47.1 µg/m³ is well within the range of “very unhealthy” air quality levels and above 2021’s annual average of 45.9 µg/m³. Much more work is needed to keep Karachi’s more than 18 million people safe from air pollution.

Karachi’s air quality suffers due to vehicles emissions, industrial activity, brick kiln activity, crop residue burning, and naturally occurring dust storms (1). Large numbers of aging vehicles combined with weak emission regulations frequently creates poor air quality days (2). Factories operate with minimal pollution controls. Additionally, rapid urbanization, accompanying construction work, and the region’s dry climate contribute to increased airborne dust levels.

Stronger, better enforced industrial pollution and vehicle emissions policies are desperately needed to control Karachi’s pollution at its source

Poor air quality in Karachi, Pakistan on March 21, 2025. Source: IQAir Map.

4. Kinshasa, Democratic Republic of the Congo

Kinshasa is the capital and largest city in the Democratic Republic of the Congo (DRC). Its average annual PM2.5 concentration in 2024 was 58.2 µg/m³, a sharp increase from 2023’s average annual concentration of 15.5 µg/m³. 

In 2024, the DRC was the second most polluted country in Africa, after Chad. As is too often the case throughout much of the continent, both nations lack comprehensive air quality monitoring. While some monitoring exists in the DRC, many more reliable and consistently operating stations are needed to help measure poor air quality affecting millions of people in the vast nation. 

Known air pollution sources include indoor cooking with wood and charcoal, forest fires, and regional agricultural and industrial activities (3).

Air quality in Kinshasa, Democratic Republic of the Congo on March 21, 2025. Source: IQAir Map.

Air quality in Kinshasa, Democratic Republic of the Congo on March 21,2025. Source: IQAir Map.

3. Dhaka, Bangladesh

In 2024, the average annual PM2.5 concentration in Dhaka reached 78 µg/m³. While a modest improvement over 2023’s annual average of 80.2 µg/m³, it is still a notable rise from the 2022 average of 65.8 µg/m³.

The capital of Bangladesh, Dhaka’s air pollution originates from multiple sources, including vehicle emissions, brick kilns, dust from roadways, industrial activity, household cookstoves, plastic burning, and unmanaged waste sites (4). 

There are an estimated 1,200 brick kilns in the country – 790 of which are operating illegally and are not approved by Bangladesh’s Department of Environment (5). To combat this pollution source, the government is demolishing illegal kilns and closing kilns using wood or low-quality coal. While addressing emissions from brick production remains a challenge, authorities aim to introduce technological advancements and stricter controls to curb pollution.

Air quality in Dhaka, Bangladesh on March 20, 2025. Source: IQAir Map.

2. Lahore, Pakistan

Lahore, Pakistan faced hazardous air quality in 2024, with an annual average PM2.5 concentration of 102.1 µg/m³. Once the most polluted city in the world in 2022, it’s an annual average that continues to rise in recent years: from 86.5 in 2021 to 99.5 in 2023. Every year since 2017, the city has endured hazardous level air quality.

14 million residents in Lahore regularly experience thick smog due to seasonal crop burning in Punjab Province, heavy vehicular emissions, and widespread pollution from brick kilns. 83% of Lahore’s poor air quality comes from vehicle emissions (6).

Local air quality activists continue to press for more widespread air quality monitoring, government transparency, and increased public awareness, but major obstacles remain in reducing pollution sources.

Air quality in Lahore, Pakistan on March 20, 2025. Source: IQAir Map.

1. Delhi, India

More than 32 million people live in Delhi, India, making it the second-largest city on Earth. In 2024, Delhi found that its average annual PM2.5 concentration had climbed to 108.3 µg/m³, up from 102.1 µg/m³ in 2023. Delhi ranked as the fourth most polluted major city in both 2021 and 2022 and the fifth in 2023, demonstrating a continually worsening trend in air quality.

The city's pollution is fueled by regional crop burning, vehicle emissions, coal power plants, and landfill fires. In October 2024, India’s Supreme Court reaffirmed clean air as a fundamental right, ordering the central and state governments to strengthen pollution control (7). It found limited action on stubble burning despite past rulings and demanded compliance reports. In November, the Court criticized Delhi officials for “serious lapses” in enforcing emergency pollution measures (8).

Hazardous and unhealthy air quality in Delhi, India on March 25, 2025. Source: IQAir Map.

What you can do

Air pollution can profoundly harm human health, but solutions exist. You can contribute to cleaning your own city’s air pollution by taking these actions:

• Advocate for change: Contact local representatives to push for stronger air quality policies and regulations. 

• Reduce personal emissions: Use energy-efficient appliances, walk, bike, or take public transport when possible.

• Stay informed: Download a free air quality app to monitor pollution levels. When air quality is poor, minimize outdoor exposure, purify indoor air, or wear a high-quality mask.

• Protect kids at school: Advocate for schools in your area to join the Schools4Earth program.

• Join the clean air movement! Become a data contributor. Community-driven data collection improves pollution awareness and empowers people to take action.

The takeaway

Reliable air quality data is essential to understanding and addressing urban air pollution. Unfortunately, many regions, including Africa, West Asia, Latin America, and the Caribbean, still lack comprehensive air monitoring systems. 

Global, real-time access to air quality data enables people to take necessary precautions, influence policy, and reduce pollution at its source. Expanding air quality monitoring worldwide can save lives and improve public health outcomes.