Bangladesh is the world’s most polluted country and Delhi is the most polluted capital. But India also has the most air quality monitors in South Asia – while some wealthy petro-nations have virtually none.

The air quality global ranking of cities for 2023 has been released by a Swiss firm, IQAir, which has been reporting this annually for over six years now. 

Never before has one country dominated the top spots for the worst air quality to the extent that India does, but the report also exposes massive gaps in monitoring pollution in the global south which stem from a lack of funds, political will or both. Air pollution is linked to over eight million deaths annually, or almost 16 per minute, and is considered a major health risk.

Nine of the top 10 most polluted cities are in India, up from six the previous year. Meanwhile, 42 cities in the top 50 are in India, up from 39; and an astounding 83 cities in the top 100 are Indian (up from 63 and 65 in the previous two years).

Delhi is back to being the most polluted capital of the world, the fifth time in the last six years. Its PM 2.5 level has averaged over 102 micrograms per cubic metre, up 10 units from the previous year. WHO’s safe guideline is just 5 micrograms. 

The report by IQAir summarises PM2.5 air quality data from 7,812 cities spanning 134 countries, regions, and territories. It sourced the data from 30,000 air quality monitoring stations operated by research institutions, governmental bodies, universities and educational facilities, non-profit organizations, private companies, and citizen scientists. 

Report exposes gaps in air quality monitoring

The data, however, cuts two ways. While it shows how dire the crisis is in India, it also exposes major gaps in monitoring. Take South Asia for starters. The world’s top three most polluted nations are all here: Bangladesh, Pakistan, and India in that order. But in Bangladesh, only two places monitor air quality, while Pakistan has 10 sites. India monitors 256 cities . 

“In Southeast Asia as a whole, 74% of the cities in the region are in India. This increase in monitoring shows the Indian government’s awareness of the country’s pollution problem, and the way to begin addressing it is to have a robust monitoring network, which India is actively doing,” a spokesperson from IQAir told Health Policy Watch. 

The lack of monitoring in other regions is stark. In Africa and South America, it raises questions of inequity and funding. The report only has data from 79 places in Africa and 219 in all of Latin America and the Caribbean. In sharp contrast, the United Kingdom alone has 219 monitoring sites, Europe 2,004, and the US has 3,242. 

In West Asia, where some countries have among the highest per capita income and GHG emissions globally, the absence of more widespread monitoring may raise questions of political will or priorities. Iraq for example has only two places with data, Saudi Arabia has three, and the UAE, a federation of seven member states, also only has three.

How the data is collected

Although some countries may have more monitors than reflected in the report, IQAir says it only uses data that meets its threshold. Chad, for instance, was the most polluted country in 2022, but it did not meet their data inclusion standards for the latest report, neither did cities like Hotan in China and Peshawar in Pakistan which are still polluted but are not included in the top 10 most polluted cities this year.

Over the years, the report has come to be extensively quoted – last year it was cited some 4,000 times according to the spokesperson. 

The report endorses a rising trend of the use of a major change in monitoring tech and that is low-cost sensors. In India, for example, the official, regulatory grade while very accurate may cost about 10 times more than the low-cost ones.

Authorities are now rolling these out by the hundreds in some of the heavily polluted regions including in Bihar, home to the world’s #1 most polluted place. Of the roughly 30,000 monitors used for the 2023 World Air Quality Report, most (61%) are low-cost monitors. The margin of error is approximately 10%, a spokesperson said.

World’s worst polluted city, and country

The world’s most polluted city is Begusarai in the east Indian state of Bihar. Its pollution level averaged 118.9 micrograms/cubic meter, 24 times the WHO’s safe limit. The most polluted country is Bangladesh which, at 79.9 micrograms, is more than 15 times higher than the safe limit. The two are hundreds of kilometres apart but air pollution connects them. 

“Due to its geographical location, Begusarai experiences a stream of pollution from various parts of India. This also explains why Bangladesh is the most polluted country in the world. Pollution from northern and southern India is funneled in by winds and affects the entirety of eastern India and Bangladesh. This is known as transboundary pollution.”

The Begusarai-Bangladesh link starkly illustrates the one big hope of tackling air pollution and that is for creating partnerships between governments and authorities. Transboundary pollution or the concept of a common air mass – creating an airshed – across political or administrative boundaries is seen as a cost-effective and most impactful option for reducing pollution. 

Climate change, pollution, and pollen allergies 

Significantly, the report warns that climate change could be exacerbating air pollution. Fossil fuel emissions account for 65% of global CO2 emissions and are also the primary cause of the majority of PM2.5-related deaths, it says, highlighting the interconnected relationship between air quality and climate change.

With extreme heat events becoming more severe and frequent, in many regions, intense pollution events may coincide with extreme heat, where weak winds hinder ground-level ventilation thereby allowing pollutants to accumulate. The frequency of such events is expected to increase. 

Changing climate patterns are also stretching out pollen seasons and making these more intense with increased levels of grass and tree pollen emissions due to changing climate patterns. 

Tackling climate change and air pollution jointly is inevitable for policymakers. The question is, can they deliver quickly enough?

Image Credits: Wikipedia, Sumitmpsd , IQAir.