Bangladesh, Pakistan and India have the worst air pollution in the world, with concentrations of particulate matter more than 10 times the recommended maximum, a report has found.
The 2023 World Air Quality Report, released by air purifier company IQAir, found 124 of 134 countries analysed exceeded World Health Organisation guidelines for particulate matter up to 2.5 microns in size (PM2.5).
These tiny particles are regarded as some of the most dangerous air pollutants and are linked to often-fatal conditions such as lung cancer and heart disease.
Many Middle Eastern cities have high levels of PM2.5, including Baghdad and Cairo, which are the world's fifth and 10th polluted capitals, respectively.
The Gulf nations fared poorly in the ranking, with the UAE seventh-worst for air pollution and Kuwait, Qatar and Bahrain all listed in the top 15. Meanwhile, fewer than 10 per cent of the countries or regions for which data was collected have pollution levels that adhere to WHO guidelines.
The report also found, however, that the PM2.5 concentration has fallen in the most polluted cities in West Asia, a region that includes the Middle East.
Aidan Farrow, a senior air-quality scientist at Greenpeace International, branded air pollution "a global health catastrophe" that required urgent action.
The report showed air pollution often had "inequitable consequences" and there was a "need to implement the many solutions that exist to this problem", he said.
"Local, national and international effort is urgently needed to monitor air quality in under-resourced places, manage the causes of transboundary haze and cut our reliance on combustion as an energy source," he said.
Ranked as the most-polluted country, Bangladesh has a PM2.5 concentration of 79.9 µg/m3 (micrograms per cubic metre), which is more than 15 times the World Health Organisation’s recommended maximum of 5µg/m3. In Pakistan and India, the concentrations are 73.7 µg/m3 and 54.4 µg/m3, respectively.
Human-made and natural factors mean that areas spanning these three countries have, the report says, "the worst air pollution conditions in the world".
Brick kilns, the burning of agricultural waste, cremations and the use of solid fuel for cooking and heating contribute to the poor air quality.
Road transport is another key source of PM2.5 in South Asia and around the world.
New Delhi is classed as the world’s most-polluted capital, with a PM2.5 concentration of 92.7 µg/m3, followed by Dhaka, the Bangladeshi capital, with 80.2 µg/m3. Islamabad in Pakistan is the world’s ninth-most polluted capital, with 42.4 µg/m3.
Tajikistan in the neighbouring region of Central Asia is also highly polluted, with a concentration of 49.0 µg/m3, the fourth-highest in the world.
Other heavily polluted countries are, from fifth to 10th worldwide, Burkina Faso (46.6 µg/m3), Iraq (43.8 µg/m3), the UAE (43.0 µg/m3), Nepal (42.4 µg/m3), Egypt (also 42.4 µg/m3) and the Democratic Republic of Congo (40.8 µg/m3).
The UAE is not the only Gulf nation high on the list, with Kuwait in 11th place (39.9 µg/m3), Bahrain in 12th (39.2 µg/m3) and Qatar 13th (37.6 µg/m3).
The Emirates has taken steps to tackle pollution through the launch in 2022 of the UAE National Air Quality Agenda 2031.
Sandstorms are also a factor in increased PM levels in desert countries found in the Middle East.
A study of Riyadh in Saudi Arabia, published in 2021 in the journal Science of the Total Environment, found that sandstorms were linked to increased PM levels and higher levels of ozone and CO.
While several of the world’s 20 most polluted capitals are in the Middle East, including Baghdad (45.8 µg/m3), Kuwait City (39.9 µg/m3), Manama (39.2 µg/m3), Abu Dhabi (38.2 µg/m3) and Doha (37.6 µg/m3), the report said pollution levels had fallen in West Asia’s nine most-polluted cities.
"In 2023, there is only one city with an annual average above 50 µg/m3, whereas there were five such cities in 2022," the report said.
Ras Al Khaimah is the most-polluted city in West Asia, with a PM2.5 concentration of 52.0 µg/m3, followed by Dhahran in Saudi Arabia (46.5 µg/m3), Baghdad, Dubai (43.6 µg/m3) and Kuwait City. The 10 least-polluted cities in the region, all in Israel, are typically much smaller.
Officials from Ras Al Khaimah, however, dispute the report, saying their own monitoring devices have measured particulate matter at far lower levels.
"Our national stations show the air quality index being 37 (good) and PM2.5 has a value of 25 µg/m3," Saif Al Ghais, director general of the Environment Protection and Development Authority in Ras Al Khaimah, told The National.
Other nations high on the most-polluted list are Indonesia, in 14th place, Rwanda (15th), Zimbabwe (16th), Ghana (17th), Kyrgyzstan (18th), China (19th) and Libya (20th).
The report uses PM2.5 readings from 30,000 air-quality monitoring stations at 7,812 sites in 134 nations or regions.
PM2.5 are considered among the most hazardous particulate pollution because their tiny size means they penetrate deep into the lungs and, the US Environmental Protection Agency reports, may enter the bloodstream.
The report also includes data for Mexico (46th with 20.1 µg/m3), Palestine (55th with 18.6 µg/m3), Israel (56th with 17.8 µg/m3), the Philippines (79th with 13.5 µg/m3), the US (102nd with 9.1 µg/m3) and the UK (112th with 7.7 µg/m3).
Africa is described as "the most under-represented continent" when it comes to air-quality monitoring.
"In many parts of the world the lack of air-quality data delays decisive action and perpetuates unnecessary human suffering," Frank Hammes, IQAir’s global chief executive, said in a statement.
"Air-quality data saves lives. Where air quality is reported action is taken, and air quality improves."
Only 10 of the 134 countries or regions analysed had pollution levels below the WHO recommended maximum, with many tending to be sparsely populated.
French Polynesia is the least polluted, with a PM2.5 concentration of 3.2 µg/m3, followed by Mauritius (3.5 µg/m3), Iceland (4.0 µg/m3), Grenada (4.1 µg/m3), Bermuda (also 4.1 µg/m3), New Zealand (4.3 µg/m3), Australia (4.5 µg/m3), Puerto Rico (4.5 µg/m3), Estonia (4.7 µg/m3) and Finland (4.9 µg/m3).
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