That is a joke.
Do you know why there is so much pollution in a city?
Because it is a city. Everything is in walking distance
at least that is the progressives plan.
Cars mean you can go where you want whenever you want;
that is bad.
All the smart people moved out of the cities.
That is not racist that is survival of the fittest
AKA natural selection read your Darwin directly
not modern media misinterpretation of it.
If you aren't smart enough to figure it out, then it is
not my responsibility to fix your situation.
That is not racist. That is nature.
Just calling it a city and saying people are being made to walk isn't the whole picture.
Even if everyone living full time in, say, NYC walked or chose public transportation, that doesn't stop tourists from driving through to see the sights, people of means traveling with a paid driver (often paid for by their company), delivery vehicles, people who make a living with their cars (Uber, Lyft, taxis...), and out-of-town commuters who don't have access to public transportation where they live outside the city. I've read of people driving 2-3 hours a day to commute into NYC just so their family can live in a better location.
Things that contribute to pollution: Tall buildings that block the wind from recycling the air and moving pollution elsewhere, the "concrete jungle" effect with paved streets and parking lots, concrete sidewalks, and the enormous number of buildings impacts the weather by absorbing heat quickly and releasing it slowly compared to just soil and plants, and so on. Natural wind breaks can also trap pollution inside the neighboring city which is the case with LA and the mountains to its East.
Those factors have nothing to do with race. The problems would exist if only Whites lived in these cities. The supposition that pollution in these places impacts minorities more is purely coincidental because of the make-up of large cities.
I'll bet there are mostly White cities that have the same problems, but they won't make these kinds of studies. Including them would disprove the thesis.