I still have to see a workable plan for emissions reduction that the rich cannot circumvent (except banning cars altogether, which would create outrage).

Tax entering the city center? Not a problem for the rich, who can pay easily. Tax cars depending on emissions? The same. Allow electric cars only? The rich have money to buy a Tesla. Allow only even or odd license plates depending on the day? The rich can buy two cars, one with odd and another with even license plate. Allow entering only if you use a paid public parking lot? The rich can pay for that. Disallow non-residents? The rich can buy a flat in the center.

Let's not fool ourselves, saving the planet and people's lungs mean that some things that are now widely reachable have to become scarce. And however we frame it, elites will always have better access to scarce resources. Still, I'd rather save the planet and my lungs than do nothing. And we can always tax the rich more to compensate.

A tax for entering the city center would be much more equitable.

My expectation is that this one plan creates exactly such a tax in practice, but it's privately collected by the few people rich enough to own land there.