Even within California there are smog-exempt counties. This makes perfect sense, things like excess NOx simply don't matter if the population density is low enough which incidentally is also true of a lot of the rest of the country. CA is the strictest with smog-related, going as far as barring federal (non-CA) vehicles from being registered unless they're 7500+ miles on the odometer. Tint should be limited to 70% VLT nationally really, but that's another topic. Other than that some north-eastern states have safety inspections which makes total sense given the rust. By developed country standards we have it very easy.