This is a dumb take. NYC for example is 68th on the list. Mecxico City is in a depression in a mountain plateau, and car exhaust and other stuff gets trapped there. Dehli has the problem of agricultural burning in a neighboring state. Bejing among other things is still surrounded by industry and gets a lot of its power from coal, both of which are resolvable issues and they've made progress.
Everything in the top 25 of the list but Seoul is in a developing country and most of them use coal power or are in unfavorable geographies for clearing smog/air pollution.
Washington D.C. isn't even on the list and Paris, London, Berlin, Sydney, and Tokyo aren't in the top 60. All of the top 25 are industrial, poor, poorly situated geographically, or some combo thereof.
COP isn’t about localized particulate pollution. You’re confusing different issues. Yes, decarbonizing might fix a lot of their air quality issues, but it’s really largely about agricultural burning.
Everything in the top 25 of the list but Seoul is in a developing country and most of them use coal power or are in unfavorable geographies for clearing smog/air pollution.