for the younger people, when I was young in the 1970’s the smog was plentiful and they worked on non-pollution. It got very much cleaned up and no one remembers the massive effort to convince people to pay extra for things, so catalytic converters and such could help with pollution. Also, in the 1970’s a nearby small lake would freeze over every winter. I can’t remember it being safe to skate on one day since 2003.