These descriptions remind me of Pittsburgh back before the Clean Air Act in the US— one apparently had to pack a second white shirt with them to work as the first was soiled with smoke by the end of the day. Buildings were and are still stained black decades after air quality had improved. My environmental history professor while studying in Pittsburgh was being treated for lung cancer in spite of never having smoked, and he thought it likely due to how smoky the city used to be.

Pittsburgh's downtown and many poorer neighborhoods were located in deep valleys full of heavy industrial installations.

I hope India makes the same progress on air quality as it develops that many richer countries have. Seeing things like its maturing domestic electric scooter industry is a reason for hope.