> improved the situation significantly
That's just yet another coping mechanism, I believe.
I lived in Krakow in ~2015, and live there now. It's the same. It smells the same, it looks the same, the polution levels are the same, and the number of days like today in a year is the same.
That's not what the data [1] says.
[1] https://powietrze.malopolska.pl/aktualnosci/wyniki-pomiarow-...