I spent some time in Krakow and it has horrible air quality. Summer feels normal like any other city, but certain times during the winter it's difficult to see due to the smog. See the below video for reference.

https://www.youtube.com/watch?v=x7nxugvTmJo

Wow darn I'm never throwing the stone at China again, seeing this in Europe, so close to home !

Were you in summer? The problem with air pollution is rather seasonal and while in warmer months it's not an issue, winters are terrible.

Source: I lived in Kraków for 4 years.

Yeah I was, so that was probably it.

It's so bad that Dynatrace, who is hiring in Gdańsk (another Polish city), is trying to convince devs from Kraków to move there with this: http://zmiensrodowisko.pl/

In the whole area. Where I spent time people still use coal heating and you had garbage pick up once a week (and you had to tip), so even tho burning garbage in the stove is illegal you surely knew when a neighbor was doing it. Part of my coming back home culture shock was not seeing cars covered in sooth.

Smarter neighbors segregate their garbage. For burning during the day, and for burning during the night.