Air Pollution: Cities Failing To Breathe Easy

Air pollution is a significant environmental threat, causing millions of premature deaths each year. It is caused by various factors, including vehicle emissions, coal-burning power plants, industrial emissions, and wildfires. While some cities have successfully improved their air quality through interventions and policies, others continue to struggle with poor air quality, with dangerous levels of pollutants such as PM2.5 and NO2. These cities are predominantly located in low- and middle-income countries, with India and Asia being the most common. This disparity highlights the urgent need for effective policies and interventions to reduce air pollution and protect public health.

Cities with the worst air pollution in 2024

Air pollution is a critical issue that affects cities worldwide, and while some cities have made significant strides in improving air quality, others continue to struggle with poor air quality that poses risks to the health and well-being of their residents. Here is an overview of cities with the worst air pollution in 2024:

Byrnihat, India

Byrnihat, a city in northeastern India, topped the list of cities with the worst air pollution in 2024. The city recorded a PM2.5 concentration of 128.2 micrograms per cubic meter, which is alarmingly over 25 times higher than the World Health Organization's recommended limit. This level of air pollution poses serious health risks to the residents, including increased chances of respiratory issues and other adverse health effects.

Delhi, India

Delhi, the capital territory of India with a population of over 30 million people, recorded the second-worst air pollution levels in 2024. The city experiences severe winter air pollution driven by crop burning in nearby states, stagnant cold air, and weak wind patterns that trap smog over the capital. Delhi's air pollution has far-reaching consequences for the health and quality of life of its residents.

Other Cities in India, Pakistan, and Asia

In addition to Byrnihat and Delhi, several other cities in India, Pakistan, and other parts of Asia are among the most air-polluted in 2024. While specific data for each city may vary, the overall trend highlights the prevalence of poor air quality in this region. Rapid urbanization and industrialization contribute to the high levels of air pollution in these areas.

Beirut, Lebanon

Beirut, the capital city of Lebanon, is another urban center that struggles with air pollution. While specific data for 2024 may not be readily available, it is known for having NO2 levels that exceeded even the least stringent WHO guidelines in previous years. This indicates that Beirut continues to face challenges in maintaining healthy air quality for its residents.

Shenyang and Shanghai, China

Both Shenyang and Shanghai, two populous Chinese cities, have been identified as having NO2 levels that exceed the WHO guidelines. While China has made efforts to improve air quality, such as implementing controls on power plant and industrial emissions, these cities continue to battle air pollution, especially from vehicle emissions and coal-burning power plants.

It is important to note that air pollution data and rankings may vary depending on the specific pollutants measured and the methods used to collect the data. Additionally, local policies and interventions can significantly impact air quality, with some cities showing improvements while pollution worsens in others. The health implications of air pollution are severe, and it is crucial for policymakers and governments to prioritize initiatives that promote clean air and safeguard the well-being of their citizens.

Cities lacking air quality monitoring stations

Air pollution is a critical issue that poses a serious threat to public health and the environment. While various cities have implemented interventions to improve air quality, there are still several urban areas that lack adequate air quality monitoring stations and have failed to show significant improvements in reducing air pollution.

One of the key challenges in addressing air pollution is the lack of monitoring stations in many cities. According to reports, some of the most polluted cities lack air quality monitoring equipment and health data. This deficiency hinders the ability to accurately assess the extent of the problem and develop effective solutions. Without proper monitoring, cities cannot implement targeted interventions or measure the success of their initiatives.

For instance, cities in India, Pakistan, and other parts of Asia consistently rank among the most air-polluted cities globally. In 2024, India alone accounted for 11 of the top 20 cities with the worst air pollution. Byrnihat, a city in northeastern India, recorded a PM2.5 concentration of 128.2 micrograms per cubic meter, which is alarmingly higher than the World Health Organization's recommended limit. Unfortunately, the lack of monitoring stations in these highly polluted regions makes it difficult to track and address the issue effectively.

Moreover, cities in low- and middle-income countries often struggle with inadequate air quality monitoring infrastructure. According to the latest urban air quality database, a staggering 98% of cities in these countries with more than 100,000 inhabitants fail to meet the World Health Organization's air quality guidelines. This indicates a widespread lack of monitoring resources and effective policies to address air pollution in these regions.

The absence of air quality monitoring stations has significant implications for public health and environmental sustainability. It impedes the ability to identify and address pollution hotspots, track the progress of interventions, and protect vulnerable populations from the harmful effects of polluted air. To effectively tackle air pollution and improve the health and well-being of urban residents, it is crucial for cities to invest in monitoring infrastructure and prioritize the implementation of sustainable practices.

Interventions targeting local pollution

Local policies have improved air quality in some cities, while pollution has worsened in others. Cities often lack air quality monitoring stations and health data, making it challenging to assess the effectiveness of interventions. However, city-level data can help inform targeted efforts to curb urban air pollution and improve public health.

A broad range of interventions targeting local pollution sources have been implemented, including those addressing industrial, residential, vehicular, and multiple sources. For instance, interventions targeting vehicular sources include low-emission zones, while residential interventions may involve a coal ban. These interventions aim to improve air quality and reduce particulate matter and other air pollutant concentrations.

The World Health Organization (WHO) plays a crucial role in supporting countries' efforts to tackle air pollution. WHO's Air Quality and Health Unit works in areas such as knowledge, evidence, and measuring progress. Additionally, the WHO Global Air Quality Guidelines (AQG) offer guidance on thresholds and limits for key air pollutants, along with interim targets to promote a gradual shift towards lower pollutant concentrations.

While the evidence base for the effectiveness of specific interventions is mixed, most studies suggest that interventions do not worsen air quality or health. The challenge lies in establishing causal relationships between interventions and outcomes, and future evaluations should employ more standardized and reliable methods to improve the quality of individual studies and enhance confidence in the findings.

Climate change and air pollution

Local policies have improved air quality in some cities, while pollution has worsened in others. For example, Beijing, China, reduced its PM2.5 levels by 36% in five years through controls on power plant and industrial emissions, as well as new fuel quality and vehicle emission standards. London's Ultra Low Emission Zone initiative delivered a 36% reduction in NO2 in the first six months. In contrast, cities with high levels of NO2, such as Beirut, Shenyang and Shanghai, collectively home to over 53 million people, exceeded even the least stringent WHO guideline.

Particulate matter (PM2.5) and nitrogen dioxide (NO2) are two main pollutants in urban environments. PM2.5 comes from vehicle emissions, coal-burning power plants, industrial emissions, and other sources. These particles are extremely small, measuring 2.5 micrograms or smaller, and can easily enter the lungs and bloodstream, impacting health in various ways. NO2 is also linked to the aggravation and development of asthma symptoms, especially in children.

Climate change mitigation efforts, such as reducing short-lived climate pollutants (SLCPs) and greenhouse gas (GHG) emissions, can have co-benefits for air quality. ICLEI recommends an integrated approach to local governments, and over 43% of actions registered by cities in the carbonn Climate Registry have positively improved air quality. However, rapid urbanization increases the number of people breathing polluted air, and most cities lack air quality monitoring stations and health data.

Air pollution is a serious health threat, affecting vulnerable groups such as children, older adults, and people with lung diseases. It can trigger asthma attacks, harm lung development, and even lead to premature births and lower birth weights. Addressing air pollution requires a complementary approach, targeting both ground-level and upper-atmosphere emissions, with interventions at the local level playing a crucial role in improving air quality in cities.

Cities with the worst air pollution in the US

While there is no up-to-date information on the cities with the worst air pollution in the US, the American Lung Association's "State of the Air 2025" report ranks cities based on their levels of ozone and two measures of particle pollution in 2021, 2022, and 2023. This report found that nearly half of the people in the US live in areas where the air quality is poor, with over 156 million people residing in counties that received a failing grade for either ozone or particle pollution. More alarmingly, more than 42 million people live in counties that received a failing grade for all three air pollution measures.

Particle pollution, or fine particulate matter (PM2.5), is one of the main pollutants in urban environments, along with nitrogen dioxide (NO2). These tiny particles, measuring 2.5 micrograms or smaller, can easily be inhaled and enter the lungs and, in some cases, even the bloodstream, causing various adverse health effects. Nitrogen dioxide, which also comes from vehicle emissions, coal-burning power plants, and industrial emissions, is linked to asthma symptoms and the development of asthma in children.

While local policies and interventions have successfully improved air quality in some cities worldwide, pollution has worsened in others. For example, Beijing, China, reduced its PM2.5 levels by 36% in five years through controls on power plant and industrial emissions, as well as new fuel quality and vehicle emission standards. London's Ultra Low Emission Zone initiative also resulted in a 36% reduction in NO2 levels in the first six months after its launch in 2019.

In the US, the Clean Air Act has driven pollution reduction for over 50 years, and the US Environmental Protection Agency (EPA) plays a critical role in monitoring and enforcing air pollution regulations. However, staffing and funding cuts endanger the EPA's ability to continue its vital work in protecting public health from the serious health threats posed by air pollution.

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