India was among 83 of the world's 100 most polluted cities by 2023

(CNN) — All but one of the world's 100 cities with the worst air pollution last year were in Asia. According to a new report. The climate crisis plays a major role in poor air quality, which puts the health of billions of people around the world at risk.

Most of these cities – 83 – are located in India and all of them exceed the World Health Organization (WHO) guidelines for air quality by more than 10 times. Report by IQAirIt monitors air quality around the world.

The study focused specifically on fine particulate matter, or PM2.5, the smallest but most dangerous pollutant. Only 9% of the more than 7,800 cities analyzed worldwide met the WHO standard for air quality, 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 Hammes, CEO of IQAir Global. “In general, in some of the most polluted countries, it can shorten people's lives by three to six years. Before that, it can cause years of suffering that could be completely avoided if we had better air quality.”

When inhaled, PM2.5 can penetrate lung tissue and reach the bloodstream. They come from sources such as the burning of fossil fuels, dust storms and forest fires, and are associated with Asthma, Heart and lung diseasesCancer and others Respiratory diseasesas well as in children with cognitive impairment.

Begusarai, a city of half a million people in the northern Indian state of Bihar, was the world's most polluted city last year, with an average annual PM2.5 concentration of 118.9, 23 times higher than the WHO's guidelines. The Indian cities of Guwahati (Assam), Delhi and Mullanpur (Punjab) are next in the IQAir rankings.

Across India, 1.3 billion people, or 96% of the population, live with air quality seven times higher than WHO guidelines, the report said.

Central and South Asia were the regions with the worst results globally, as they had 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. The report ranked Lahore 5th, New Delhi 6th and Dhaka 24th as major population centers.

Hams said significant improvements in the region's pollution levels are unlikely without “major changes in terms of energy infrastructure and agricultural practices.”

“The concern in many parts of the world is that things that cause outdoor air pollution sometimes cause indoor air pollution,” he added. “So cooking with dirty fuel will create indoor exposures that are many times greater than what you see outside.”

A global problem

IQAir found that 92.5% of 7,812 locations in 134 countries, territories and territories that surveyed average air quality last year exceeded WHO PM2.5 guidelines.

Only 10 countries and territories a Air quality “Healthy”: 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. A step study Published in the journal BMJ in November, air pollution from fossil fuels kills 5.1 million people worldwide each year. For its part, WHO mentions 6.7 million people die annually from the combined effects of environmental and indoor air pollution.

According to the IQAir report, the man-made climate crisis driven by the burning of fossil fuels plays a “fundamental” role in affecting air pollution levels.

The climate crisis is changing weather patterns, creating changes in wind and precipitation that affect the spread of pollutants. Climate change will worsen pollution as extreme heat becomes more severe and frequent.

The climate crisis is causing more severe wildfires and longer, more intense pollination seasons in many regions, exacerbating health problems related to air pollution.

“The causes of the climate crisis and air pollution often overlap,” Hammes said. “Anything we can do to reduce air pollution will have a huge long-term impact on improving our climate gas emissions, and vice versa.”

Regional classification

North America was hit hard by wildfires in Canada from May to October last year. In May, average monthly air pollution in Alberta was nine times higher than the same month in 2022, the report says.

For the first time, Canada has overtaken the US in regional pollution rankings.

Wildfires also affected US cities such as Minneapolis and Detroit, where annual pollution averages increased by 30% to 50% compared to the previous year. Columbus (Ohio) was the most polluted large US city in 2023 for the second year in a row. However, major cities such as Portland, Seattle and Los Angeles saw significant declines in their average annual pollution levels, the report said.

However, in Asia, pollution levels increased across much of the region.

According to the report, China reversed a five-year trend of declining pollution levels. Chinese cities were dominant World ranking Poor air quality, but a series of clean air policies implemented over the past decade have improved the situation.

A step Course from last yearThanks to the measures taken, the average life expectancy of Chinese citizens has increased by 2.2 years. But thick smog returned to Beijing last year, where citizens saw a 14% increase in the average annual concentration of PM2.5, IQAir reported. China's most polluted city, Hotan, ranks 14th in IQAir's ranking.

In Southeast Asia, only the Philippines recorded a decline in annual pollution levels from the previous year, the report said.

Indonesia It was the most polluted country in the region, with a 20% increase compared to 2022. Indonesia, Vietnam and Thailand had cities that exceeded WHO guidelines for PM2.5 by more than 10 times, the report said.

Last month, Thai authorities ordered civil servants to work from home due to unhealthy levels of pollution in and around the Thai capital, Bangkok, Reuters reported. On Friday, the resort city of Chiang Mai became the most polluted in the world due to smog caused by seasonal agricultural burning.

Inequality… and a positive aspect

The report highlights a worrying disparity: Africa, South America and the Middle East lack monitoring stations, 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 remains significantly underrepresented. According to IQAir, only 24 out of 54 African countries had sufficient data from their observatories.

New places added to the 2023 ranking include seven African countries, including Burkina Faso, the world's fifth-most polluted country, and Rwanda, ranked 15th.

Masked people walk on Kartavya Road amid heavy pollution in New Delhi, India on November 5, 2023. (Credit: ARUN SANKAR/AFP via Getty Images)

Many of the countries that topped last year's most polluted list were not included in 2023 due to a lack of available data. Among them, Chad was the most polluted country in 2022.

“There's still a lot of hidden air pollution on the planet,” Hames said.

A positive aspect is the growing pressure and civic commitment from communities, NGOs, businesses and scientists to monitor air quality.

“Ultimately, it's great because it shows governments that people care about,” Hummes said.