Warsaw, Poland

Radio Poland: Smog crisis in Warsaw prompts free public transport

So that makes at least, in recent memory: Warsaw, Beijing, Tehran, London, Paris (off the top of my head)… where else? Why is heavy smog such a big issue suddenly in diverse locations?

Warsaw City Hall on Thursday for the first time gave residents free access to public transport across the capital in a bid to reduce high air pollution.
Warsaw Deputy Mayor Michał Olszewski said: “We urge residents to leave their cars at home and use the public transport system. We ask them not to use their fireplaces.”
He added: “Residents should also limit the time they spend outside, especially in the eastern districts of Warsaw, where the level of pollution might be especially high.”

Thanks to @zim_ek.