That sounds horrible for yellow and red cars. I hope all new cars are green.
[1] https://www.germanemissionssticker.com
[2] https://en.wikipedia.org/wiki/European_emission_standards
The result is that almost no one goes there anymore. All the inner city shops are closing down - while the mall style shopping centers on the outskirts are flourishing.
Walkable cities sound great in theory. Until you realize that shopping groceries _really_ sucks when you have to carry full bags for 3 kilometers or have to use over-filled public transport.