In the list of the 20 most polluted cities in the world in 2024, only one was not in Asia, shows a study.
Most of these cities – 13 – are the most populous country in the world, India, where economic growth at a rapid pace is mainly fueled by coal. In this country, hundreds of millions of people live in large cities marked by heavy and congested traffic.
Four other of the most polluted cities in the world are in the neighboring country, Pakistan. There is then one in China and one in Kazakhstan.
The only city to appear on the list outside Asia is N’Djamena, the capital of Chad in Central Africa. Chad was considered the country with the worst indicators in air pollution.
In turn, as regards North America, the most polluted cities were all in California.
The IQAIR study, a Swiss company that monitors the global quality of air, concretely analyzed the fine particles, also known as PM2.5, one of the smallest but also more dangerous pollutants.
PM2.5 have as their sources the combustion of fossil fuels, dust storms and forest fires. They have 1/20 of the width of a human hair. And because they are so small, they can surpass the natural defenses of our body, entering our lungs or our bloodstream.
Particles cause irritation and inflammation and have been associated with breathing problems and chronic kidney diseases. Exposure to these particles can cause cancer, strokes or heart attacks. They are also associated with a high risk of depression and anxiety.
A bird flies, crossing a thick layer of fog in Nova Deli, India, on November 20, 2024 (Manish Swarup/AP/FILE)
N’Djamena, in Chad, was considered the most polluted city in 2024 (Irem Demir/Anadoli/Getty Images)
The World Health Organization (WHO) states that annual average levels of PM2.5 should not exceed five micrograms per cubic meter.
Byrnihat, an industrial city in northeastern India, recorded a PM2.5 concentration of 128.2 last year – that is, more than 25 times above the WHO standard.
“I feel very sad, powerless that Byrnihat continues to lead the list,” lamented 26-year-old Suman Momin, who lives in this city with about 70,000 inhabitants to CNN.
This young guilt the factories surrounding the city, the growing construction industry and the removal of trees as factors that contribute to the air to be increasingly toxic.
“At this moment, pollution is particularly serious. You can not see anything, there is dust everywhere, my eyes burn,” he says.
“I don’t leave home without wearing a mask,” he puts together.
Twelve other cities on the most polluted list are in India.
The capital of the country, Nova Deli, stands out as the most polluted capital in the world for the sixth consecutive year, with a concentration of PM2.5 of 91.8. The study also included six satellite cities: Faridabad, Loni, Deli, Gurugram, Noida and Greater Noida.
Last November, a dense layer of fog covered Deli: he interrupted flights, blocked the sight of the buildings and led the city’s head of the city to declare a “medical emergency.”
Countries in Asia and Africa among the most polluted in the world
In 2024, the average air quality in Chad was more than 18 times above the PM2.5 safety limit established by the World Health Organization (WHO), which is five micrograms per cubic meter. It presents itself as the country with the worst air quality at global level. Bangladesh and Pakistan were right behind.
In the chart above, the average concentration of PM2.5 in 2024 in countries with pollution levels seven times higher than WHO limit is shown in micrograms by cubic meter. PM2.5 are one of the six major air pollutants recognized and monitored in the world, at the expense of its significant adverse effects on human health.
In a general analysis, India – the most populous country in the world with 1.4 billion inhabitants – fell from third to fifth position compared to the previous year, according to the study.
Still, the study points out that air pollution “remains a significant burden on health, reducing life expectancy by about 5.2 years.”
A man wears a mask while going through a small iron factory in Lahore, Pakistan, on January 16, 2024 (km Chaudary/AP)
The neighbors of India, Bangladesh and Pakistan, which together have about 400 million inhabitants, were, respectively, the second and third most polluted countries in the global level with regard to PM2.5 molecules, according to the study.
China, which used to master global rankings on the worst air quality, recorded a slight improvement, the same study points out.
China’s annual average concentration of PM2.5 descended from 32.5 micrograms per cubic meter to 31, with air quality improving megacities such as Beijing, Shanghai, Chengdu, Canton and Shenzhen.
China is the largest carbon dioxide issuer in the world, but in recent years it has carried out actions against air pollution, namely in cities that feed its economic growth. It has also promoted an expansion of solar and wind energy.
However, in February, two environmental groups drew attention to the alleged Chinese plans to build new coal factories with a capacity of 100 gigawatts, the largest number of the last decade.
All 20 most polluted cities in the world exceeded ten more times, by 2024, WHO guidelines for PM2.5 showed the study of IQAIR.
Data failures
“Air pollution remains a critical threat to both human health and the stability of the environment. Still, there are wide layers of the population that remain unknowingly their exposure levels,” says Frank Hammes, IQAIR CEO.
Iran and Afghanistan were not included in the latest edition of this study due to the lack of available data.
The monitoring of air quality in Southeast Asia is also a problem, as almost all countries have “significant gaps in actions that are the responsibility of governments,” the study found.
Vehicles to circulate, causing high levels of air pollution in Hanois, Vietnam, on March 5, 2024 (Nhac Nguyen/AFP/Getty Images)
In 2024, 173 of 392 cities in this region had no public monitoring stations. Cambodia, for example, had none.
These problems should be aggravated after the US has announced that they would fail to share data on air quality collected at their embassies and consulates worldwide, at the expense of “financing limitations,” said Associated Press.
“Air quality data saves lives,” insists Hammes.
“They create a very necessary conscience, form political decisions, guide interventions regarding public health, enable communities to take steps to reduce air pollution and protect future generations.”
The worst cities in North America
Only 17% of the 8,954 cities analyzed globally by IQAIR registered an air quality that attended the WHO guidelines, the study says.
Cities with the worst air pollution in North America were Ontario, Bloomington and Huntington Park – all in California, the study says.
Overall, the United States of America recorded a significant reduction in PM2.5 levels last year, with the annual average to go down 22% compared to 2023.
North America has long ago has effective air quality monitoring systems, contributing 56% of the total number of soil air quality monitoring stations that were included in the IQAIR report. Thus, scientists help in their continuous research on air quality and help those responsible for adopting measures in their public health decision making.
Only 12 countries, regions and territories recorded concentrations of PM2.5 below the WHO guidelines. Most of them are in Latin America, Caribbean and Oceania.
The study appeals to governments that funds destinations for renewable energy projects and that “reinforce the limits of emissions for vehicles and industrial activities”.
These are advice that Suman wants Byrnihat authorities to follow, so as to prevent his city from appearing at the top of the most polluted list in the world in the next edition of the study.
“The people around me have also developed breathing problems over the years,” says CNN.
“This is the place where I was born. I am from here. And I don’t want to leave. We want governments to do more, unite and work to improve our lives.”
AishWarya S Iyer contributed to this article
