Yeah. The EU doesn't allow individual states to set their own emissions standards for cars for similar reasons, even though they're nowhere near as unified as t

Yeah. The EU doesn't allow individual states to set their own emissions standards for cars for similar reasons, even though they're nowhere near as unified as the US in general - it affects trade between the member states and therefore is centrally controlled. (This has caused some problems due to the European NO2 and PM5 standards for diesels being rather on the lax side.)