Explanation:

Rajasthan's Bhiwadi has been found to be the most polluted city not only in the country but also the world in 2021.

This was revealed in the list of most polluted cities in the world by IQAir, a Swiss air quality technology company.

Bhiwadi, the industrial town in Alwar district, is known for its high pollution levels and was ranked fourth in 2020.

PM2.5 particulate matter consists of fine aerosol particles measuring 2.5 microns or smaller in diameter.

The most common natural sources for PM2.5 are dust storms, sandstorms, and wildfires. Common chemical constituents such as sulfates, nitrates, black carbon, and ammonium, and common human-made sources like internal combustion engines, power generation, industrial processes, agricultural processes, construction, and residential wood and coal burning also make up the air quality.

Bhiwadi had a PM2.5 concentration of 106.2 ug/m³ in 2021, which increased from 95.5 ug/m³ in the previous year.

The second city from Rajasthan in the list is Jodhpur, which has been placed 45th with an average annual PM2.5 concentration of 67.8 ug/m³.