Around 61 or 62 California decided that smog was a problem that had to go so they appointed a smog commission and jumped in with both feet, literally. What ensued was a mish-mash of regulations and some not so effective devices, blew up a good 292 Y block in a 57 Ford with that garbage. Fast forward to 2012 and California still has smog and will always have smog because of their geographic location and diesel engines amongst other things. They can't blame industry anymore since they ran them all out, so who's left?
Like a fellow I worked with at Douglas in the 60's said "As long as there is a smog commission we'll have smog".