World Air Quality Report 2021

by | Apr 22, 2022 | Environmental News

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Key Findings of the World Air Quality Report 2021

World air quality reports present an overview of the global condition of air quality. A Swiss organization, IQAir, publishes a world air quality report every year. They base their measurements of air quality on the concentration of Particulate Matter (PM) 2.5 present in the air over a specific region. By publishing these reports, IQAir hopes to inspire and motivate governments, businesses, companies, NGOs, and ordinary people like you and me to create a healthier living space and atmosphere for everyone, including our planet. Today, world leaders consider air pollution as one of the biggest threats to the health of humans and the Earth. Air pollution claims around 7 million lives around the world every year. Now let us look at the key findings of the world air quality report 2021.



The World Air Quality Report 2021 ranked Bangladesh as the most polluted country of the year. The PM 2.5 level recorded in Bangladesh was 76.9 µg/m³. This figure is much in excess of the WHO (World Health Organization) recommended maximum level of 5 mg per cubic meter. The report declared Chad the second most polluted country in the world, followed in third place by Pakistan.

The World Air Quality Report 2021 also revealed that not one country in the entire world met the air quality standards set by WHO. Around the world, the report found that 93 countries had PM 2.5 levels that were ten times that of the recommended level.

The report found New Delhi to be the most polluted city in the world. Delhi recorded a PM 2.5 level of 85.1 µg/m³. Dhaka followed New Delhi as the second most polluted city in the world, with a PM 2.5 level of 78.1 µg/m³.

Air Quality in India

Among 117 countries, the report ranked India as the world’s 5th most polluted country. Based on the report’s findings, New Delhi continued to be the most polluted city in the world for the fourth consecutive year. 11 out of the 15 most polluted cities in Central and South Asia were in India. India’s PM 2.5 level in 2021 reached 58.1 µg/m³, ending a three-year trend of improving levels of air quality.

There are a total of 6 metro cities in India. Every metro city, excluding Chennai, witnessed a rise in air pollution levels in 2021. Delhi was the most polluted metro city, followed by Kolkata, Mumbai, Hyderabad, Bengaluru, and Chennai. The report showed that the PM 2.5 level in Mumbai was 46.4 µg/m³. This is almost nine times that of the WHO recommended limit. The World Air Quality Report 2021 listed 35 Indian cities under the category of ‘worst air quality.’ Bhiwandi in Rajasthan topped this list, while Ghaziabad in Uttar Pradesh came in second place.

Air Quality in India

To protect citizens from the diseases induced by air pollution, the Indian Ministry of Environment, Forest, and Climate Change in 2019 enacted the National Clean Air Program (NCAP). The NCAP aims to reduce PM concentrations by 20-30% by 2024. The program also seeks to increase air quality monitoring in major cities and implement a nation, state, and city-specific clean action plan.

Why Does the Report Base Its Findings on PM 2.5 Concentrations?

PM 2.5 refers to all particulate matter less than or equal to 2.5 microns in diameter. They include solid particles and liquid droplets present in the air. We consider PM 2.5 to be one of the air pollutants most harmful to human health. Due to its small size, it stays for a long time in the environment. Can’t comprehend how small 2.5 microns really is? Picture a strand of your hair. On average, human hair is approximately 70 microns in diameter, making a single strand of your hair 30 times larger than a PM 2.5 particle.

Various sources generate PM 2.5. The matter commonly includes black carbon, ammonium, nitrates, and sulphates. Human sources of PM 2.5 include power generation, combustion engines, constructional activities, industries, etc. Natural sources of PM 2.5 include dust storms, sandstorms, and wildfires. PM 2.5 emitted from various sources exhibits a varying degree of chemical and physical characteristics. However, they all have one thing in common- their presence above a certain limit is dangerous to public health.

Because of their incredibly tiny size, we can easily inhale these particles. They are capable of getting lodged in our lungs, sometimes even in our bloodstream. This can adversely affect our health and lead to respiratory problems, cardiovascular problems, and lung cancer, among other diseases.

Way Forward for India and the World

If anything, the World Air Quality Report 2021 has shown us just how much we’re falling short of meeting WHO prescribed standards and the consequences that will occur if we continue to fail. Along with damaging human health, air pollution is also one of the biggest threats to the environment. It alters behavioural and reproduction patterns in species, causing their populations to decrease. The survival of the Earth depends on a delicate balance between all life forms. We cannot survive if everything else dies. To collectively protect ourselves and the Earth, we must urgently address why we’re failing to meet our air quality targets.

Governments around the world need to pass strict legislation that prohibits the emissions of PM above a specific limit. Governments could also incentivize clean air vehicles, such as electric vehicles, and mass implementation of renewable sources of energy to power public transport.

We need to adhere to WHO’s 4-pillar strategy to combat the adverse effects of air pollution on public health. The four pillars include:

1. Expanding the knowledge base

2. Monitoring and reporting

3. Global leadership and coordination

4. Strengthening institutional capacities

Apart from adhering to these four pillars, we must also address injustices within our society. Poorer people are the ones that are most exposed to the adverse effects of air pollution. Therefore, the government must levy an environmental tax on industries that pollute above a recommended standard.

The World Air Quality Report 2021 found New Caledonia, the U.S Virgin Islands, and Puerto Rico to be the world’s top three cleanest countries. We could learn and model these countries to reduce our emissions and reduce air pollution. Of course, we may be different from these countries in several aspects such as economic growth, population, etc. But small steps go a long way in bringing about positive change.



  • Dr. Emily Greenfield

    Dr. Emily Greenfield is a highly accomplished environmentalist with over 30 years of experience in writing, reviewing, and publishing content on various environmental topics. Hailing from the United States, she has dedicated her career to raising awareness about environmental issues and promoting sustainable practices.

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