Context: According to the World Air Quality Report 2023, Delhi has the worst air quality of any capital city in the World.

About World Air Quality Report

• Published By: It is Published  by IQAir, a Swiss Organization.

• IQAir: A Swiss air quality technology company, prepares the annual world air quality reports based on data from monitoring stations operated by governments, institutions and organisations across the world.

• Data Collection: It collected data from 7,812 places throughout 134 countries, regions, and territories.

Key Highlights of the Report

• Poor Quality Air: India has the third poorest air quality, with an average annual PM2.5 concentration of 54.4 micrograms per cubic meter.

• India performed better than only two of its neighbors, Bangladesh and Pakistan.

• In 2022, India was ranked as the eighth most polluted country with an average PM2.5 concentration of 53.3 micrograms per cubic metre.

• Most Polluted Country: While Bangladesh remained the world’s most polluted country, with an average PM2.5 concentration of 79.9 micrograms per cubic meter, Pakistan ranked second, with a level of 73.7.

• Polluted Cities of India and World: For the fourth year in a row, Delhi was named the world’s most polluted capital city.

• Begusarai, Bihar, has been described as the world’s most polluted urban area.

• Ten of the top eleven most polluted cities in the world are from India, with the other being Lahore, Pakistan.

• PM 2.5 Levels in India: 96 percent of India’s population experiences  PM2.5 levels that are more than seven times the WHO annual PM2.5 recommendation.

• It is estimated that 1.36 billion people in India experience PM2.5 concentrations exceeding the World Health Organisation (WHO) recommended annual guideline level of 5 micrograms per cubic metre.

Impact

• Exposure to PM2.5 air pollution leads to and exacerbates numerous health conditions, including but not limited to asthma, cancer, stroke and lung disease.

• Exposure to elevated levels of fine particles can impair cognitive development in children, lead to mental health issues, and complicate existing illnesses, including diabetes.

What is Particulate Matter?

• About: It is made up of solid particles and liquid droplets in the air.

• Production: PM can originate in a variety of locations. In general, any form of burning or dust-generating activity produces PM. 

• Variation in Sizes: PM comes in a variety of sizes. 

• Larger particles are typically derived from the soil. 

• Smaller particles result from the combustion of fossil fuels, such as petrol in automobiles, diesel in trucks, and coal used in power plants.

• Categories of Particulate Matter: Primary PM is directly emitted by a smokestack or tailpipe. Chemical processes cause secondary PM to form downwind of gaseous emission sources.

• PM 2.5: PM 2.5 is an atmospheric particulate matter with a diameter of less than 2.5 micrometers, which is approximately 3% the diameter of a human hair.