This issue of In Focus reflects on the 2024 World Air Quality Report released by IQAir on 11-March 2025. This is the 7th annual report from IQAir, which is a Swiss-based air quality technology company that seeks to empower individuals, organizations and communities to breathe cleaner air through information, collaboration and technology solutions.
The 2024 analysis on PM2.5 air quality results, is based on measurements and data collected from more than 40,000 air quality monitoring stations across 8,954 locations in 138 countries, territories, and regions, analysed by IQAir’s air quality scientists by aggregating, validating and calibrating air quality data from a wide variety of sources, including governments, private citizens and organizations.
This year’s publication highlights alarming trends in the world’s most polluted countries, territories and regions. The key findings from the 2024 World Air Quality Report are as follows:
The full report, including a detailed region/country review, and other useful data and information can be found in IQAir’s website, using the following link: https://www.iqair.com/world-air-quality-report
The following table and map are based on the WHO global air quality guidelines, which were updated in 2021. At the time the organisation reduced the annual PM2.5 concentration from 10 µg/m³ to 5 µg/m³, reflecting on the significant impact of air pollution on global health. IQAir has divided the world into seven groups to easily identify countries and regions facing significant health risks due to high concentrations of PM2.5 pollution by a simple colour code. Each group corresponds to a range of PM2.5 concentrations aligned with WHO annual guideline or target values.
Countries, territories, and regions in Africa and Central and South Asia continue to report the highest population-weighted annual average PM2.5 concentrations. While Africa’s air quality monitoring network is expanding, data availability remains inconsistent, with only 24 out of 54 countries or territories reporting data in 2024. The Middle East is also underrepresented and requires more robust monitoring. Although Iraq was added to the report this year, key omissions remain, including Afghanistan, Iran, and Oman.
Overall, 10 new countries or territories were included in the 2024 report compared to 2023, with the majority coming from Africa (4) and the Latin America and Caribbean region (5). Globally, only 12 countries or territories recorded PM2.5 concentrations below the WHO guideline of 5.0 µg/m³, most of which were in the Latin America and Caribbean or Oceania regions.
Using the same colour scheme, the following table ranks the countries’ population weighted, 2024 average PM2.5 concentration (μg/m³) in descending order:
According to the IQAir report, 31 out of 138 countries globally exceed targeted PM2.5 levels by more than 5-fold, which is a marginal improvement versus the 2021 World Air Quality report. The vast majority of the countries in the first two most PM2.5-polluted countries are located in Africa and Asia, followed by the Middle East, where air quality controls and improvements are implemented with mixed success.
Going through the negative ranking by country, some specific examples have been picked to highlight some progress or further deterioration over the last three years.
The 5th most PM2.5-polluted country is India, maintaining its position in the table unchanged over the last three years. In fact, India’s indicated population weighted, 2024 average PM2.5 concentration (μg/m³) improved, from 58.1 to 50.6. Numerous measurements to improve the air quality have been implemented, among those the full roll-out of the Bharat-6 specification for transportation fuels, which are largely aligned with Euro-6 standards, but the country has a long way to go before its people will start enjoying clean air. Till date, six of the world’s ten most polluted cities are in India. Air pollution remains a significant health burden in India, reducing life expectancy by an estimated 5.2 years, according to the University of Chicago’s Air Quality Life Index report, published in 2023.
In October 2024, India’s Supreme Court affirmed that breathing clean, pollution-free air is a fundamental right. The Court found that the federal and local government must more effectively control air pollution at its source.
The next most polluted major economy in the IQAir report is Indonesia in 15th place, climbing the ladder in the wrong directions, from 17th spot in 2021. The pollution index increased, from 34.3 to 35.5 μg/m³. The nationwide average PM2.5 levels still exceeded the WHO annual guideline by more than tenfold. In 2024, no Indonesian city met the WHO’s air quality standard. Persistently poor air quality in Indonesia continues to endanger the health of residents, as rapid urbanization and industrialization have significantly increased the demand for power in the country, where coal burning generates two-thirds of the electricity. Over the last few years Euro-4 fuel emission standards have been rolled, yet not fully country-wide. An Ethanol-blending programme for gasoline has been initiated, which surprised clean-fuel advocates amid the lack of production infrastructure in the country.
China remains in the 2nd category of the most polluted countries, ranked in 21st spot, insignificantly changed over the last three years. However, the country’s PM2.5 pollution index continues to improve, indicated at 31.0 μg/m³ in 2024 versus 32.6 μg/m³ in 2021. This development was confirmed in key cities such as Beijing, Shanghai, Chengdu, Guangzhou, and Shenzhen, all of which reported reductions in annual average concentrations. Overall, 323 cities in China recorded lower year-on-year concentrations, as Beijing continues to tighten its national PM2.5 targets and prioritize key areas for reducing pollution and smog. Officials have set ambitious goals to lower the national annual average PM2.5 concentration to below 28 µg/m³ by 2027 and below 25 µg/m³ by 2035.
Major sources of air pollution in China include dust storms, coal production, cement manufacturing, and transportation. While coal plants continue to be commissioned, there are far fewer in 2024 than in previous years. Permits for the construction of new refineries have also been severely restricted, while solar and wind energy production is expanding in some provinces. Emissions requirements for cars and fuels meet world-leading standards, which has helped the country reduce the burden on the transportation sector over the years.
For the years to come, challenges for Africa will remain. The collection of air quality data has greatly improved, but rapid urbanization, population growth, and till-date still limited air quality monitoring exacerbate Africa’s pollution crisis. The region’s population is expected to triple by 2050. Chad remains the world’s most polluted country, with the Democratic Republic of the Congo, Uganda, Rwanda and Burundi also featuring in the list of the ten most PM2.5-polluted countries worldwide, all exceeding WHO standards by more than seven-fold. We consider it as essential for the clean fuels lobby to support local initiatives to improve fuel quality standards to contribute the region’s air quality control.
The Middle East still has seven countries among the world’s most polluted countries in the top-two categories, with PM2.5-pollution exceeding targeted standards by more than five-fold. The overall situation remains largely incoherent, and there has been only marginal progress in terms of region-wide fuel-standards, with some countries in the Middle East adhering to advanced, international standards, while others trail far behind of do not even have any quality standards. All attempts to harmonize fuel standards across the region have failed till date, which is admittedly difficult to achieve in a politically divided environment.
However, PM2.5-pollution results in Saudi Arabia, Qatar, the UAE and Kuwait have improved, as awareness about the implications of poor air quality increases. Unsurprisingly, fuel quality standards in these countries are among the highest in the region.
However, the global air quality situation remains alarming and emissions from fossil fuels continued to rise in 2024 and severe wildfires contributed to a surge in land-use emissions, pushing global climate goals further out of reach.
The Global Carbon Budget report, published during the UN's COP29 climate summit in Azerbaijan, said global CO2 emissions are set to total 41.6bn MT in 2024, up from 40.6bn MT in 2023. The bulk of these emissions are from burning coal, oil and gas. Those emissions would total 37.4bn MT in 2024, up by 0.8% from 2023, the report stated.
Countries agreed under the 2015 Paris Agreement to try to stop global temperatures rising more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) to avoid climate change's worst impacts, and some scientists have warned that the 1.5C target can no longer realistically be met.
The Global Carbon Budget also reveals that emissions are projected to decrease significantly in the EU (down 3.8%) and slightly in the US (down 0.6%) in 2024. They are expected to increase slightly in China (up 0.2%), and increase significantly in India (up 4.6%) and the rest of the world (up 1.6%, including international shipping and aviation).
A UNICEF analysis in February 2025, revealed the staggering impact of toxic air on millions of children and Asia and the Pacific, urging immediate action to protect their health and future, calling it a silent killer. The report states that air pollution during the dry season from February to April is linked to over 100 deaths in children under five every day, robbing them of their chance to live, learn, and thrive.
500 million children is East Asia and the Pacific live in countries with unhealthy levels of air pollution. Household air pollution, caused by solid fuels used for cooking and heating, is linked to more than half of all air pollution, related deaths in children under five. 325 million children live in countries where average annual PM2.5 levels exceed WHO guideline levels by more than five times, and 373 million live in countries with unhealthy levels of nitrogen dioxide. Additionally, 91 percent of the children in the region live in countries where ozone pollution exceeds WHO guideline levels. Nearly half of the PM2.5 in countries with the highest levels of this pollutant, came from the burning of fossil fuel, biomass fuel, and agriculture waste, which also generate the greenhouse gases driving climate change.
To summarize, achieving the WHO PM2.5 emission targets and guidelines will remain a tough challenge, in most countries and regions around the world. While developed economies increasingly adopt advanced environmental protection measures and standards, less developed countries will struggle to keep pace due to constraints or lack of financing, also as technology and infrastructure deficits in these regions will continue to pose major challenges for the foreseeable future.
As far as the pollution from transportation fuels is concerned, the clean fuels industry needs to keep up its efforts to propose, introduce and help to implement higher quality standards, particularly targeting countries and regions in Africa, the Middle East and South-East Asia. Examples of positive combating of environmental pollution, i.e. in Europe, China and other parts of North-East Asia, as well in some countries in the Middle have shown that that higher fuel emission standards do make a serious contribution to improving air quality.
Raising existing fuel standards and implementing higher standards for transportation fuels are certainly a viable possibility. In this context, fuel ethers, such as MTBE and ETBE are two of the clean fuel components utilized to achieve higher standards, which will enhance fuel quality and octane ratings by replacing other more harmful components, both leading to air quality improvements. The capacity and production of ethers is ample and supply is readily available, making this a realistic, cost-effective and easy-to-implement solution.
Various studies have found that ethers (MTBE/ETBE)-based oxygenated fuels generally reduce emissions of PM2.5, CO, NOx, and VOCs compared to ethanol gasoline blends. While showing some emission reductions, ethanol gasoline blends resulted in higher emissions of PM2.5 and VOCs, the two main precursors/components of urban smog. In addition, ethers (MTBE/ETBE) gasoline blends also reduced emissions of air toxics like 1,3-Butadiene, Acrolein, and PAHs compared to ethanol blends, which increased emissions of certain air toxics.
In this issue of our “In Conversation with” we talked to Mr. Jeff Hove, acting Vice President and Executive Director at the Fuels Institute. In recent years we have seen some initiatives to consider policies to ban the sale of vehicles equipped with internal combustion engines (ICE), predominantly emerging in Europe, but also spreading out in parts of Asia.
In this issue of our “In Conversation with” we talked to Dr Tilak Doshi, an energy sector consultant based in Singapore. Dr Doshi shared his views and observations about the global “2050 decarbonisation” plan and move towards Electric Vehicles (EVs) with us. We would like to thank Dr Doshi for his efforts to comprehensively answer our questions which provide some highly valuable and very interesting insights into this matter, highlighting a range of topics often overlooked in the political discussion between the various stakeholders in the race to save the world from impending climate catastrophe.
In this issue of our “In Conversation with” we talked to Dr Sanjay C Kuttan, Chairman of the Sustainable Infrastructure Committee at Sustainable Energy Association of Singapore (SEAS).
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