The article discusses air pollution in Indian cities, caused by factors like population growth and vehicle density. The researchers collected data on air quality at different times of day and in various areas of the cities. They used this data to create maps showing pollution levels across the cities. The study found that pollution levels are highest in the morning and evening, vary by season, and are influenced by factors like wind speed and direction. People living or working near busy roads are more likely to experience health issues like respiratory problems.