The air of Bangladesh was the most polluted worldwide while not a single country managed to meet the World Health Organization's (WHO) latest quality standard last year, a new global study suggests.
With this, the South Asian nation’s air quality with the average annual PM2.5 concentrations of 76.9 micrograms per cubic metre has remained the worst since 2018.
In continuation of its “unhealthy” air quality among major cities across the world for the past few months, Dhaka was ranked the second-worst city in 2021 considering its air pollution, the findings add.
Sadly, Dhaka was the second-most polluted city globally in 2020 too.
The PM2.5 level in the megacity was measured at 78.1 micrograms per cubic metre last year, according to the World Air Quality Report-2021 unveiled on Tuesdday.
IQAir, a Swiss pollution technology company that monitors air quality, prepared the report analysing PM2.5 air pollution measurements from 6,475 cities in 117 countries, regions and territories.
Fine particle pollution, known as PM2.5, is commonly accepted to be the most harmful, widely-monitored air pollutant and has been found to be a major contributing factor to health effects such as asthma, stroke, heart and lung diseases. PM2.5 leads to millions of premature deaths every year.
Bangladesh was followed by Chad, Pakistan, Tajikistan and India, respectively, on the list of worst-affected countries. India's overall pollution levels worsened last year.
New Delhi (India) was the world’s most polluted capital city in 2021 for the fourth consecutive year, followed by Dhaka (Bangladesh), N’Djamena (Chad), Dushanbe (Tajikistan) and Muscat (Oman).
The air quality debacle occurred as smog even rebounded in some regions after a Covid-related dip.
The WHO recommends that average annual readings of small and hazardous airborne particles known as PM2.5 should be no more than 5 micrograms per cubic metre after changing its guidelines in September, saying that even low concentrations caused significant health risks.
But only 3.4% of the surveyed cities met the standard in 2021. As many as 93 cities saw PM2.5 levels at 10 times the recommended level.
Central and South Asia had some of the world’s worst air quality in 2021 and was home to 46 of the world’s 50 most polluted cities, the report mentions.
“The only two cities that met updated WHO PM2.5 guideline were Zhezqazghan and Chu (Kazakhstan),” it adds.
"There are a lot of countries that are making big strides in reduction," said Christi Schroeder, air quality science manager with IQAir. "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."
“It is a shocking fact that no major city or country is providing safe and healthy air to their citizens according to the latest WHO air quality guidelines,” said IQAir CEO Frank Hammes.
"This report underscores just how much work remains to be done to ensure that everyone has safe, clean and healthy air to breathe. The time for action is now."