Really? I thought it was mostly solved by regulations that require filters at the industrial sites (and aren’t those used in Diesel cars, too?). Actually, what happens with the gunked-up filter material? Can the captured sulfur and nitrogen be used? I think you can use nitrogen as a fertilizer?

True, i looked up a bit more information on it and apparently it was at its height around the 80s, so I may have misremembered time a little bit.

Acidic rain.

I don’t remember any of the specifics anymore but it boils down to: Trees and plants died in masses, scientists and the general population got together and we changed what caused it.