It is supposed to get better over time though. I mean at least that's the sales pitch. Globalization was supposed to lift all boats. If you remember the air quality in Beijing used to be the absolute worst but it has allegedly improved a lot recently.
I don't know where the flaw in the logic was but I think the idea was first you have to become wealthier and with more money comes a better quality of life.
Globalization does lift all boats. We get cheap stuff without having to make it, and they get jobs and pollution.
It got better in Beijing because they moved factories to more rural areas, not because manufacturing is any less dirty.