The city with the highest air pollution from PM2.5 is Kanpur , India, according to a report published in 2018 by the World Health Organization (WHO).
Specifically, the peak was recorded in 2016, with an average of 173 μg of PM.25 per cubic meter, 17 times the recommended maximum.
Kanpur is located on the shores of the Ganges River and is an important industrial center. It covers an area of more than 1,000 km² and has a population of around 2.7 million inhabitants according to the 1991 census .
Industrial and vehicle emissions are instrumental in polluting the air of Kanpur with PM2.5 particles.
They are particles that have a diameter of less than 2.5 microns (μm is one millionth of a meter), such as fine soot; while PM10 includes contaminants up to 10 microns in diameter, such as dust or pollen.
Many factories continue to burn coal to obtain the energy that their production processes require and the increase in logistics activity translates into a greater number of vehicles traveling on unpaved roads, with the consequent raising of dust and the constant emission of toxic gases.
Every year, dozens of its cities are on the most polluted list, but little or no effort is made to improve air quality. In the latest report, Delhi marginally improved its ranking to sixth , up from the most polluted city in 2014.