You might have smelled Baton Rouge before the Clean Air Act of 1990 kicked in.
And that was long after the emission cutbacks of the 1970's had taken place, back when it was really rank. But the EPA had not been around very long at that early point.
Driving across the state of Louisiana you could feel better stopping to nap in the car for a few hours in a far-away mosquito-infested rest stop next to a low-lying bayou during a flash-flood warning, rather than get a hotel room in the state capital, it smelled so toxic.
Don't ask me how I know . . .