I think that regulation is fine as long as it done in a sensible manner - I don’t want to see car manufacturers going out of business because they don’t produce the cleanest cars in the world.
Some cars pollute more than others, that is true more so now than ever. In the UK, this is dealt with two-fold:
1. Cars can only produce a certain level of various substances. Those that produce more than this are deemed unfit and will not be given a valid MOT certificate unless work is carried out to remedy the problem.
2. Heavier polluting cars, such as 4x4’s, are taxed to the hilt whereas owners of smaller engined, more environmentally friendly cars are given more of a break.
I’m uncertain as to how I feel about this setup - On one hand I applaud them for encouraging people to drive more environmentally friendly vehicles, though I don’t feel that those wanting to (or needing to?) drive bigger vehicles should be as heavily punished - Perhaps manufacturers or even Governments should be taking steps towards making such vehicles less of a burden on the environment?