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Source: The post is based on the article “IQAir report: Delhi most polluted city in world” published in “The Hindu” on 14th November 2023
Why in the News?
IQAir has released the Air Quality Index(AQI).
What is the Air Quality Index(AQI)?

| Specifications | Details |
| Released by | IQAir, a Swiss based air purifier company |
| Purpose | To measure air quality levels data from 109 countries |
| Based on | US Methodology |
| Parameter | It measures air quality levels based on the concentration of airborne particles known as PM2.5. |
What are the key findings of the IQAir Air Quality Index(AQI)?
1)Most Polluted City: Delhi was the most polluted city in the world. It was followed by Lahore, Pakistan.
— Note: Air pollution in parts of Delhi was 30 times the safe limits prescribed by the World Health Organization (WHO) contributed in part by the firecrackers.
2)Other Indian Cities in top 10 polluted cities: Kolkata was fourth on the list, followed by Mumbai in ninth place.
3)Cleanest City: Mexico City was declared the cleanest city in the world.
UPSC Syllabus: Environment



