(CNN) — All but one of the 100 cities with the world’s worst air pollution last year were in Asia, according to a new report. The climate crisis plays a significant role in poor air quality, which threatens the health of billions of people around the world.
Most of these cities – 83 – are located in India and all these cities exceed 10 times the World Health Organization (WHO) guidelines on air quality, according to the IQAir report, which monitors ambient air quality. World.
The study focused specifically on fine particulate matter, or PM2.5, the smallest but also the most dangerous pollutant. Only 9% of more than 7,800 cities analyzed worldwide recorded air quality that met the WHO standard, which establishes that annual average levels of PM2.5 should not exceed 5 micrograms per cubic meter .
“Air pollution affects every aspect of our lives,” said Frank Hames, CEO of IQAir Global. “And typically, in some of the most polluted countries, it’s probably shortening people’s lives by three to six years. And before that it will cause many years of suffering that would have been completely avoided if there had been better air quality. May go.”
When inhaled, PM2.5 enters the lung tissue, where it can reach the bloodstream. They come from sources such as fossil fuel combustion, dust storms and wildfires, and have been linked to asthma, heart and lung disease, cancer and other respiratory diseases, as well as cognitive decline in children.
Begusarai, a city of half a million in the north Indian state of Bihar, was the most polluted in the world last year, with an average annual PM2.5 concentration of 118.9, 23 times higher than WHO guidelines. It was followed by Indian cities Guwahati (Assam), Delhi and Mullanpur (Punjab) in the IQAir ranking.
The report said 1.3 billion people across India, or 96% of the population, are living with air quality seven times higher than WHO guidelines.
Central and South Asia were the regions with the worst results globally, as they were home to the four most polluted countries last year: Bangladesh, Pakistan, India and Tajikistan.
South Asia is of particular concern, as 29 of the 30 most polluted cities are in India, Pakistan or Bangladesh. Major population centers Lahore have been ranked 5th, New Delhi 6th and Dhaka 24th in the report.
Hames said the region’s pollution levels were unlikely to improve significantly without “major changes in terms of energy infrastructure and agricultural practices”.
“The concern in many parts of the world is that the things that are causing outdoor air pollution are sometimes the same things that are causing indoor air pollution,” he said. “So cooking with dirty fuel will create risks indoors that may be many times higher than what you see outside.”
a global problem
IQAir found that 92.5% of the 7,812 locations in 134 countries, territories and regions where it analyzed average air quality last year exceeded WHO PM2.5 guidelines.
Air quality was “healthy” in only 10 countries and territories: Finland, Estonia, Puerto Rico, Australia, New Zealand, Bermuda, Grenada, Iceland, Mauritius and French Polynesia.
Millions of people die every year from health problems related to air pollution. Air pollution from fossil fuels kills 5.1 million people worldwide every year, according to a study published in November in the journal BMJ. For its part, WHO indicates that 6.7 million people die per year from the combined effects of environmental and household air pollution.
The man-made climate crisis, driven by the burning of fossil fuels, plays a “fundamental” role in influencing air pollution levels, IQAir reports.
The climate crisis is changing weather patterns, driving changes in wind and rainfall, which affect the spread of pollutants. Climate change will only make pollution worse as extreme heat becomes more severe and more frequent.
The climate crisis is also causing more severe wildfires in many areas and longer, more intense pollination seasons, exacerbating health problems related to air pollution.
“The causes of the climate crisis and air pollution are very similar,” Hames said. “Anything we can do to reduce air pollution will also have a long-term impact on improving our climate gas emissions, and vice versa.”
regional classification
North America was badly affected by the wildfires that broke out in Canada from May to October last year. According to the report, the average monthly air pollution in Alberta in May was nine times higher than the same month in 2022.
And for the first time, Canada overtook the United States in regional pollution rankings.
Wildfires also affected US cities such as Minneapolis and Detroit, where annual pollution averages increased between 30% and 50% compared to the previous year. The most polluted large US city in 2023 for the second consecutive year was Columbus (Ohio). However, according to the report, big cities like Portland, Seattle and Los Angeles saw significant declines in their average annual pollution levels.
However, in Asia, pollution levels increased across much of the region.
According to the report, China has reversed a five-year trend of declining pollution levels. Chinese cities used to dominate global rankings for worst air quality, but a series of clean air policies implemented over the past decade have improved the situation.
According to a study last year, the average life expectancy of Chinese citizens increased by 2.2 years thanks to the measures taken. But thick smog returned to Beijing last year, where citizens experienced a 14% increase in average annual concentrations of PM2.5, IQAir reports. Hotan, China’s most polluted city, was ranked 14th in IQAir’s ranking.
In Southeast Asia, only the Philippines recorded a decline in annual pollution levels compared to the previous year, according to the report.
Indonesia was the most polluted country in the region, with an increase of 20% compared to 2022. According to the report, there were cities in Indonesia, Vietnam and Thailand that were more than 10 times the WHO guidelines for PM2.5.
Last month, Thai authorities ordered government employees to work from home due to unhealthy levels of pollution in and around the capital Bangkok, according to Reuters. On Friday, the resort city of Chiang Mai became the most polluted in the world due to smog generated by seasonal agricultural burning.
Inequality… and a positive side
The report also highlights a worrying disparity: the lack of monitoring stations in countries in Africa, South America and the Middle East, resulting in a lack of data on air quality in those regions.
Although Africa has seen an improvement in the number of countries included in this year’s report compared to previous years, the continent still has the lowest representation. According to IQAir, only 24 out of 54 African countries had sufficient data from their monitoring stations.
New additions to the 2023 ranking include seven African countries, including Burkina Faso, the world’s fifth-most polluted country, and Rwanda, ranked 15th.
People wearing masks walk on the Karta Path amid heavy pollution in New Delhi, India on November 5, 2023. (Credit: Arun Shankar/AFP via Getty Images)
Many countries that ranked high on the most polluted list last year were not included for 2023 due to a lack of available data. These also include Chad, which was the most polluted country in 2022.
“There’s still a lot of hidden air pollution on the planet,” Hames said.
One positive aspect is the increasing pressure and citizen commitment from communities, NGOs, businesses and scientists to monitor air quality.
“Ultimately, it’s great because it shows governments care about people,” Hames said.