As per the latest World Air Quality Report for 2022, India is now the 8th most polluted country in the world, a slight improvement dropping from the 5th position in 2021 as PM 2.5 levels dip down to 53.3 micrograms/cubic metre, despite still being over 10 times the World Health Organisations safe limit. A concerning observation is that Indian cities continue to dominate the list as 39 out of the 50 most polluted cities of the world are in India.

The report has been released by Swiss firm IQAir based on the PM 2.5 levels - a closely tracked pollutant, across 131 countries taken from over 30,000 ground-based monitors. As per the report, air pollution is the single biggest environmental threat to human health causing over 7 million premature deaths every year.

"Worldwide, poor air quality accounts for 93 billion days lived with illness and over six million deaths each year. The total economic cost equates to over $8 trillion dollars, surpassing 6.1 percent of the global annual GDP. Exposure to air pollution causes and aggravates several health conditions which include, but are not limited to, asthma, cancer, lung illnesses, heart disease, and premature mortality," the report said.

The top ten most polluted countries are Chad, Iraq, Pakistan, Bahrain, Bangladesh, Burkina Faso, Kuwait, India, Egypt and Tajikistan. Meanwhile, six countries that met the WHO PM 2.5 guideline (annual average of 5 µg/m3 or less) are Australia, Estonia, Finland, Grenada, Iceland, and New Zealand.

Indian cities dominate list of most polluted cities worldwide:

The list that covers around 7300 cities is dominated by Indian cities with 39 out the 50 most polluted cities being in the country. Lahore in Pakistan and Hotan in China are the top two most-polluted cities after which ranks Rajasthan's Bhiwadi and Delhi at the 3rd and 4th places respectively. At 92.6 micrograms, Delhi's PM 2.5 level is almost 20 times the safe limit.

14 out of the top 20 most polluted cities are in India, namely Bhiwadi, Delhi, Darbhanga, Asopur, New Delhi, Patna, Ghaziabad, Dharuhera, Chapra, Muzzafarnagar, Greater Noida, Bahadurgarh, Faridabad, and Muzzafarpur.

Among Indian metros, Delhi and Kolkata feature in the top 100 most polluted cities with PM 2.5 levels of 92.6 and 50.2 respectively. Others following are Mumbai, Bangalore, Hyderabad and Chennai. Chennai is relatively the cleanest with pollution at just 5x the WHO's safe level at a PM 2.5 concentration of 25.3.

The report has placed the economic cost of air pollution in India at $150 billion, with the transportation sector contributing to 20-35% of it. Other sources of pollution are industrial units, coal-fired power plants and biomass burning.

Delhi 'technically' no longer most polluted:

While Delhi has so far been known as the most polluted capital in the world, due to a distinction in 'greater Delhi' and New Delhi it is technically no longer the most polluted. However, both feature in top 10 with New Delhi ranked 2nd.

Surprisingly, Delhi's neighbouring cities Gurugram, Noida, Ghaziabad and Faridabad have seen a decline in pollution levels - from 34% in Gurugram to 21% in Faridabad, compared to the average PM 2.5 levels reported in previous years. Delhi has dipped barely 8%.

However, the actual levels of pollution in these cities are far higher than the Indian average with Ghaziabad's PM 2.5 average for 2022 over 88 micrograms and Gurugram's at 70. Hence at such high levels of pollution, the decline cannot be seen as an improvement - the air remains hazardous. 

31 Indian cities see double-digit decline in pollution levels:

As many as 31 cities have seen a double-digit percentage decline in pollution levels. Of these, 10 are in Uttar Pradesh and 7 in Haryana. The biggest dip in pollution of 55% has been seen in the Taj Mahal city of Agra. On the other hand, as many as 38 cities and towns have seen a rise in pollution compared to an average of previous years.

South Asia - the epicenter of air pollution:

As per the report, 72 of the top 100 most polluted cities are in South Asia, most of which are again cities in India, Pakistan and Bangladesh ranking higher in the list of the ten most polluted countries. Air pollution is a common problem with these countries sharing 'air sheds' - causing pollutants from one area to move into another.

Currently, the human cost of PM 2.5 is over two million premature deaths in the region.