Air pollution is reduced by misty light rain. The process is called wet deposition. Swarms of electric drones could mist cities with water every morning to reduce air pollution. The technology should be feasible and economically justified.

Here’s a link about wet deposition.

https://public.wmo.int/en/our-mandate/focus-areas/environmen...

Here’s a recent example of misty rain at work in the Bay Area.

https://www.reddit.com/r/sanfrancisco/comments/pj12nx/a_labo...