You obviously didn’t live in the LA area during the 80s and 90s. I vividly remember having school days where we had “smog alerts” and no one was allowed to run during recess due to air quality. You could also be standing in a place like Pasadena and not be able to see the San Gabriel Mountains (which are only a few miles away). That’s mostly a thing of the past now. The emmissions standards had and continue to have a huge impact on the air quality there and I’m baffled as to why anyone would want to walk that back (other than car manufacturers or factory/energy sector people because they can do things a bit cheaper).