A survey of pollution data from 6,475 cities showed that no country managed to meet the World Health Organization's (WHO) air quality standard in 2021, and smog even rebounded in some regions after a COVID-related dip.

The data, compiled by <a href="https://www.iqair.com/in-en/world-air-quality-report">IQAir</a>, a Swiss company that monitors air quality, shows that while no countries met the standards in 2021, only 3.4 per cent&nbsp;of the surveyed cities did.&nbsp;Based on air quality data from 6,475 cities in 117 countries, the report presents an overview of global air quality in 2021.

At least 93 cities recorded PM2.5 levels that were 10 times higher than what WHO recommended.

Also read |&nbsp;<a href="https://www.wionews.com/world/out-of-breath-population-boom-and-its-impact-on-air-pollution-452400">Out of breath: Population boom and its impact on air pollution</a>

Since changing its guidelines last year, the WHO recommends that average annual concentrations of hazardous airborne particles known as PM2.5 be no more than 5 micrograms per cubic metre. However, the WHO stresses that even low PM2.5 concentrations are harmful.

"There are a lot of countries that are making big strides in reduction," IQAir science manager Christi Schroeder said.&nbsp;

"China started with some very big numbers and they are continuing to decrease over time. But there are also places in the world where it is getting significantly worse."

The data showed that India's overall pollution levels worsened in 2021 and that New Delhi remained the most polluted capital in the world.

Also read |&nbsp;<a href="https://www.wionews.com/world/air-pollution-kills-7-million-people-per-year-estimates-who-issues-new-guidelines-414975">Air pollution kills 7 million people per year, estimates WHO;&nbsp; issues new guidelines</a>

It was also revealed that 35 of the 50 cities with the worst air quality are in India, the country is ranked as the fifth most polluted country.

"India’s annual average PM2.5 levels reached 58.1 µg/m3 in 2021, ending a three-year trend of improving air quality. India’s annual PM2.5 averages have now returned to pre-quarantine concentrations measured in 2019."

As in the previous year, Bangladesh was the most polluted country, while Chad ranked second after the African nation's data was included for the first time.

Watch |&nbsp;World Health Organization toughens its air quality standards in 16 years

<div class="videoWrapper trancodeVideo"><iframe allowfullscreen="" autoplay="1" class="includeVideo" frameborder="0" height="350" src="https://www.wionews.com/videos/world-health-organization-toughens-its-air-quality-standards-in-16-years-415262/embed" style="width:100%;max-width:560px;" width="560"></iframe></div>

China fell to 22nd place in the PM2.5 rankings in 2021, down from 14th place a year earlier with an average reading of 32.6 micrograms over the year, according to IQAir.

Hotan in Xinjiang's northwestern region is China's worst-performing city, with an average PM2.5 level reading of over 100 micrograms, due primarily to sandstorms.

After being overtaken by two Indian cities, Bhiwadi and Ghaziabad, it dropped to third on the top polluted cities list.

A survey of pollution data from 6,475 cities showed that no country managed to meet the World Health Organization's (WHO) air quality standard in 2021, and smog even rebounded in some regions after a COVID-related dip.

A survey of pollution data from 6,475 cities showed that no country managed to meet the World Health Organization's (WHO) air quality standard in 2021, and smog even rebounded in some regions after a COVID-related dip. The data, compiled by IQAir, a Swiss company that monitors air quality, shows that while no countries met the standards in 2021, only 3.4 per cent of the surveyed cities did. Based on air quality data from 6,475 cities in 117 countries, the report presents an overview of global air quality in 2021. At least 93 cities recorded PM2.5 levels that were 10 times higher than what WHO recommended. Also read | Out of breath: Population boom and its impact on air pollution Since changing its guidelines last year, the WHO recommends that average annual concentrations of hazardous airborne particles known as PM2.5 be no more than 5 micrograms per cubic metre. However, the WHO stresses that even low PM2.5 concentrations are harmful. "There are a lot of countries that are making big strides in reduction," IQAir science manager Christi Schroeder said. "China started with some very big numbers and they are continuing to decrease over time. But there are also places in the world where it is getting significantly worse." The data showed that India's overall pollution levels worsened in 2021 and that New Delhi remained the most polluted capital in the world. Also read | Air pollution kills 7 million people per year, estimates WHO; issues new guidelines It was also revealed that 35 of the 50 cities with the worst air quality are in India, the country is ranked as the fifth most polluted country. "India’s annual average PM2.5 levels reached 58.1 µg/m3 in 2021, ending a three-year trend of improving air quality. India’s annual PM2.5 averages have now returned to pre-quarantine concentrations measured in 2019." As in the previous year, Bangladesh was the most polluted country, while Chad ranked second after the African nation's data was included for the first time. Watch | World Health Organization toughens its air quality standards in 16 years China fell to 22nd place in the PM2.5 rankings in 2021, down from 14th place a year earlier with an average reading of 32.6 micrograms over the year, according to IQAir. Hotan in Xinjiang's northwestern region is China's worst-performing city, with an average PM2.5 level reading of over 100 micrograms, due primarily to sandstorms. After being overtaken by two Indian cities, Bhiwadi and Ghaziabad, it dropped to third on the top polluted cities list.

Not even one country met WHO air quality standards in 2021, India 5th most polluted country: Report

The World Health Organization strengthened its air quality guidelines on Wednesday, saying air pollution was now one of the biggest environmental threats to human health, causing seven million premature deaths a year.

It said urgent action was needed to reduce exposure to air pollution, ranking its burden of disease on a par with smoking and unhealthy eating.

"WHO has adjusted almost all the air quality guideline levels downwards, warning that exceeding the new... levels is associated with significant risks to health," it said.

"Adhering to them could save millions of lives."

The guidelines aim to protect people from the adverse effects of air pollution and are used by governments as a reference for legally-binding standards.

The UN health agency last issued air quality guidelines, or AQGs, in 2005, which had a significant impact on pollution abatement policies worldwide.

However, the WHO said in the 16 years since, a much stronger body of evidence had emerged, showing how air pollution impacts on health at lower concentrations than previously understood.

"The accumulated evidence is sufficient to justify actions to reduce population exposure to key air pollutants, not only in particular countries or regions but on a global scale," the organisation said.

Southeast Asia hard-hit

The new guidelines come just in time for the COP26 global climate summit held in Glasgow from October 31 to November 12.

The WHO said that alongside climate change, air pollution was one of the biggest environmental threats to human health. Improving air quality would enhance climate change mitigation efforts, and vice versa, it said.

The WHO's new guidelines recommend air quality levels for six pollutants, including ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide.

The other two are PM10 and PM2.5 — particulate matter equal or smaller than 10 and 2.5 microns in diameter.

Both are capable of penetrating deep into the lungs but research shows PM2.5 can even enter the bloodstream, primarily resulting in cardiovascular and respiratory problems, but also affecting other organs, said the WHO.

In response, the PM2.5 guideline level has been halved.

In 2019, more than 90 percent of the world's population lived in areas where concentrations exceeded the 2005 AQG for long-term PM2.5 exposure. Southeast Asia is the worst-affected region.

Premature deaths

"Air pollution is a threat to health in all countries, but it hits people in low- and middle-income countries the hardest," said WHO chief Tedros Adhanom Ghebreyesus.

The WHO said that while air quality had markedly improved since the 1990s in high-income countries, the global toll in deaths and lost years of healthy life had barely declined, as air quality had generally deteriorated in most other countries, in line with their economic development.

"Every year, exposure to air pollution is estimated to cause seven million premature deaths and result in the loss of millions more healthy years of life," the WHO said.

In children, this could include reduced lung growth and function, respiratory infections and aggravated asthma.

In adults, ischaemic heart disease — also called coronary heart disease — and stroke are the most common causes of premature death attributable to outdoor air pollution.

Evidence is also emerging of other effects such as diabetes and neurodegenerative conditions, the organisation said.

The WHO said the burden of disease attributable to air pollution was "on a par with other major global health risks such as unhealthy diet and tobacco smoking".

The World Health Organization strengthened its air quality guidelines on Wednesday, saying air pollution was now one of the biggest environmental threats to human health, causing seven million premature deaths a year.

The World Health Organization strengthened its air quality guidelines on Wednesday, saying air pollution was now one of the biggest environmental threats to human health, causing seven million premature deaths a year. It said urgent action was needed to reduce exposure to air pollution, ranking its burden of disease on a par with smoking and unhealthy eating. "WHO has adjusted almost all the air quality guideline levels downwards, warning that exceeding the new... levels is associated with significant risks to health," it said. "Adhering to them could save millions of lives." The guidelines aim to protect people from the adverse effects of air pollution and are used by governments as a reference for legally-binding standards. The UN health agency last issued air quality guidelines, or AQGs, in 2005, which had a significant impact on pollution abatement policies worldwide. However, the WHO said in the 16 years since, a much stronger body of evidence had emerged, showing how air pollution impacts on health at lower concentrations than previously understood. "The accumulated evidence is sufficient to justify actions to reduce population exposure to key air pollutants, not only in particular countries or regions but on a global scale," the organisation said. Southeast Asia hard-hit The new guidelines come just in time for the COP26 global climate summit held in Glasgow from October 31 to November 12. The WHO said that alongside climate change, air pollution was one of the biggest environmental threats to human health. Improving air quality would enhance climate change mitigation efforts, and vice versa, it said. The WHO's new guidelines recommend air quality levels for six pollutants, including ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. The other two are PM10 and PM2.5 — particulate matter equal or smaller than 10 and 2.5 microns in diameter. Both are capable of penetrating deep into the lungs but research shows PM2.5 can even enter the bloodstream, primarily resulting in cardiovascular and respiratory problems, but also affecting other organs, said the WHO. In response, the PM2.5 guideline level has been halved. In 2019, more than 90 percent of the world's population lived in areas where concentrations exceeded the 2005 AQG for long-term PM2.5 exposure. Southeast Asia is the worst-affected region. Premature deaths "Air pollution is a threat to health in all countries, but it hits people in low- and middle-income countries the hardest," said WHO chief Tedros Adhanom Ghebreyesus. The WHO said that while air quality had markedly improved since the 1990s in high-income countries, the global toll in deaths and lost years of healthy life had barely declined, as air quality had generally deteriorated in most other countries, in line with their economic development. "Every year, exposure to air pollution is estimated to cause seven million premature deaths and result in the loss of millions more healthy years of life," the WHO said. In children, this could include reduced lung growth and function, respiratory infections and aggravated asthma. In adults, ischaemic heart disease — also called coronary heart disease — and stroke are the most common causes of premature death attributable to outdoor air pollution. Evidence is also emerging of other effects such as diabetes and neurodegenerative conditions, the organisation said. The WHO said the burden of disease attributable to air pollution was "on a par with other major global health risks such as unhealthy diet and tobacco smoking".

Air pollution kills 7 million people per year, estimates WHO;  issues new guidelines

air-quality-guidelines

Air Quality Guidelines, News on Air Quality Guidelines, stories on Air Quality Guidelines, articles on Air Quality Guidelines, Air Quality Guidelines stories at Wion, Air Quality Guidelines news, Air Quality Guidelines latest news

air quality-guidelines

Not even one country met WHO air quality standards in 2021, India 5th most polluted country: Report

Air pollution kills 7 million people per year, estimates WHO; issues new guidelines