Air Pollution's Worst Offenders: Country Ranking

Air pollution is a pressing global issue, with 91-99% of the world's population living in areas where air quality exceeds the World Health Organization's (WHO) recommended guidelines. According to the WHO, air pollution causes over 7 million premature deaths annually, making it one of the biggest health problems of modern industrial society. While the most polluted countries are often those with emerging or developing economies, it's important to note that the most polluted countries are not always the biggest polluters. With that in mind, which country has the worst air pollution, and what factors contribute to this problem?

Bangladesh: the world's most polluted country in 2021 and 2022

Bangladesh has been ranked as the world's most polluted country in 2021 and 2022. The country's severe air pollution takes a heavy toll on its people, economy, and environment. According to the World Health Organization (WHO), the recommended limit of PM2.5, or fine particulate matter, is 10 micrograms per cubic meter (µg/m³). However, Bangladesh's capital city of Dhaka has had an average PM2.5 concentration of 77.1 µg/m³ over the past decade, more than eight times the recommended limit.

The high levels of air pollution in Bangladesh have severe health consequences for its residents. Fine particulate air pollution (PM2.5) shortens the average Bangladeshi resident's life expectancy by 6.8 years compared to the WHO guideline of 5 µg/m³. Certain areas of Bangladesh, such as Gazipur, the country's most polluted district located near Dhaka, fare even worse, with air pollution shortening lives by 8.3 years. Across the country, all 164.8 million people live in areas where the annual average particulate pollution level exceeds both the WHO guideline and Bangladesh's own national standard of 15 µg/m³.

The sources of Bangladesh's air pollution are diverse and interconnected. Vehicle emissions, industrial discharges, and the widespread use of kilns for brick-making all contribute significantly to the poor air quality. Additionally, Bangladesh's growing use of fossil fuels has not only exacerbated air pollution but also contributed to climate impacts, increasing the frequency of natural disasters like tropical cyclones and severe flooding. While the country's consumption of coal is relatively low compared to other regional actors, its pursuit of nuclear energy as an alternative has been costly.

The government of Bangladesh recognizes the urgency of addressing the air pollution crisis. The country faces challenges in transitioning to a safer and more equitable energy system while balancing growth, sustainability, and energy access. Improving data availability and accessibility can empower Bangladeshi citizens to actively participate in tackling air pollution. Additionally, the World Bank is actively supporting Bangladesh in reducing air pollution through analytical work and new investments.

Bangladesh's air quality crisis underscores the complex interplay between environmental, economic, and social factors. While the country grapples with the immediate health and environmental consequences, it also navigates the challenges of energy transition and sustainable development. By addressing these issues, Bangladesh can enhance the well-being of its population and mitigate the impacts of climate change.

India: home to the world's most polluted city, Byrnihat

Air pollution is a pressing global issue, with 91-99% of the world's population living in areas where air quality exceeds World Health Organization (WHO) guidelines. The WHO's recommended limit for PM2.5 particulate matter is 10 micrograms per cubic meter, though national guidelines may be higher.

In 2022, Chad was deemed the world's most polluted country, with a PM2.5 concentration of 89.7, a notable increase from 75.9 in 2021. Other countries that have been ranked among the most polluted in the world include Bahrain, Bangladesh, and Pakistan.

However, when considering specific cities, Byrnihat in northeastern India recorded the worst air pollution globally in 2024. Its PM2.5 concentration was measured at 128.2 micrograms per cubic meter, over 25 times higher than the WHO's recommended limit. Delhi, India, was ranked as the second-worst for air pollution in 2024, with the city experiencing severe winter air pollution driven by crop burning, stagnant cold air, and weak wind patterns that trap smog.

India's struggle with air pollution in its cities is multifaceted. Industrial emissions, vehicle exhaust, and a reliance on fossil fuels are significant contributors, exacerbated by weak regulations and unfavourable seasonal weather patterns. The impact of air pollution on health cannot be overstated, with respiratory issues, asthma, and congenital disabilities being linked to poor air quality.

Chad: the only non-Asian country in the top 20 most polluted

Air pollution is one of the biggest health problems of modern industrial society and is responsible for more than 10% of all deaths worldwide. According to the World Health Organization (WHO), 91-99% of the world's population lives in areas where air quality exceeds recommended guidelines.

In 2022, Chad was named the world's most polluted country, with a PM2.5 concentration of 89.7, a notable increase from 75.9 in 2021. Chad's air quality crisis is driven by desert dust, vehicle emissions, and biomass burning. The country's annual mean concentration of PM2.5 is 66 µg/m3, far exceeding the recommended maximum of 10 µg/m3.

Chad's location between two mountain ranges, downwind from a natural wind tunnel, makes it particularly susceptible to Saharan dust plumes from the Bodele Depression, which is one of the largest sources of airborne dust in the world. NASA estimated in 2007 that about half of the 40 million metric tons of dust that travel from the Sahara to the Amazon each year originate from the Bodele Depression.

Indoor air pollution is the single largest contributor to the negative health effects of air quality in Chad. The country's reliance on wood and charcoal for energy, with these sources providing 90% of consumed energy, contributes significantly to indoor air pollution, causing an estimated 9,600 premature deaths annually. Additionally, the common practice of unregulated waste burning, particularly in urban centers, further deteriorates air quality.

Chad's lack of policies and governance approaches to control pollution exacerbates the issue. As of 2015, National Ambient Air Quality standards and National Air Quality legislation were either non-existent or not enforced. The country faces challenges in implementing a national integrated and sustainable waste management strategy and strengthening the enforcement and regulation of industrial and vehicle emissions.

While Chad has ascended to the top of the list as the most polluted country in 2022, other countries, such as Bangladesh and Bahrain, have also struggled with poor air quality and have seen fluctuations in their PM2.5 concentrations over the years.

Bahrain: fluctuations in PM2.5 concentration

While Chad ranked as the world's most polluted country in 2022, with a PM2.5 concentration of 89.7, Bahrain has also been on this list in the past and continues to struggle with air quality. The fluctuations in PM2.5 concentration in Bahrain reflect the challenges posed by industrial emissions, heavy traffic, and regional dust storms.

Bahrain's capital, Manama, often enveloped in smog, epitomizes the country's battle with air pollution. The city's PM2.5 concentration has varied in recent years, from 59.8 in 2018 to 39.7 in 2020, and then a sharp increase to 66.6 in 2022. These levels are of concern as PM2.5 particles can infiltrate the cardiopulmonary system and enter the bloodstream due to their minuscule size.

The high levels of pollution in Bahrain are attributed to various factors, with the petroleum industry being a significant contributor. The country's economy is heavily reliant on petroleum, and companies like the Bahrain Petroleum Company (BAPCO) have initiated environmental projects to reduce pollution. For instance, BAPCO implemented the Refinery Gas Desulphurisation Project to remove sulphur from refinery gas, a move towards improving the environment. Additionally, they have invested in a base oil lubrication project, which helps reduce engine exhaust emissions.

Despite these efforts, air quality in Manama remained "unhealthy" in mid-2021, with a US AQI reading of 156. During this time, it is recommended that individuals remain indoors, and if they must go outside, they should wear good-quality masks to prevent respiratory issues.

The Kingdom of Bahrain has demonstrated a commitment to improving air quality through various initiatives. They have formed a national committee to transition to renewable and environmentally friendly energy sources, encouraging their use by government agencies, companies, institutions, and individuals. Furthermore, major industrial companies in Bahrain have taken the initiative to implement environmental projects as part of their social responsibility. These efforts are essential steps towards reducing air pollution and protecting the environment.

Pakistan: led the table in 2022

Pakistan is the world's fourth most polluted country, with air pollution causing serious health issues for its citizens. In 2022, Pakistan's PM2.5 reading was 65.81 μg/m³, placing it in the 'unhealthy' category, which ranges from 55.5 to 150.4 μg/m³. This level of pollution is detrimental to the health of all members of the population and is estimated to reduce the average Pakistani resident's life expectancy by 3.3 to 3.9 years.

The main sources of air pollution in Pakistan include vehicle emissions, industrial pollution, waste burning, and the use of coal for electricity generation. Pakistan's megacities, such as Lahore, Peshawar, Gujranwala, and Faisalabad, are among the most polluted in the world, with air quality index (AQI) readings of up to 1900 in Lahore. The high levels of fine particulate matter (PM2.5) in the air are of particular concern, as they are considered one of the most deadly pollutants. Exposure to PM2.5 has been linked to various health issues, including breathing problems, worsening of asthma, and congenital disabilities.

The Pakistani government has an obligation to protect its citizens' right to a clean and healthy environment under international human rights law. However, the government has continued to expand coal power, with Prime Minister Shehbaz Sharif inaugurating two new coal-fired power plants in Sindh in 2022. This reliance on fossil fuels, especially coal, has severe costs for both human and environmental health.

To address the air pollution crisis, Pakistan needs to transition to renewable energy sources, phase out fossil fuels, regulate and enforce air quality standards, and develop urban green spaces. The country's proximity to highly polluted countries such as India and China also contributes to its air quality issues, highlighting the need for regional cooperation and the implementation of global environmental standards.

While Pakistan has made significant progress in expanding access to electricity, with 95% of the population having electricity in 2022, it is crucial to balance this development with sustainable practices to protect the health and well-being of its citizens and the environment.

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