All of these cities you list are actually stifled by pollution and are (very) far from being clean. I happen to live in one of those and visit regularly others in the list.
The problem is far from being solved. However, it's true that the pollution per inhabitant is much lower than in the Silicon Valley.
You must be crazy. You can lick the sidewalks in Zurich, although you'd probably be arrested. It's certainly the cleanest major city I've seen. And the tram come every minute.
That's either a pretty silly troll or you haven't travelled much outside of affluent Western Europe. I've also been to most of those cities and can only say, if you think they're "stifled by pollution" then your first 10 minutes in Beijing are going to be rather eye-opening (or is that eye-watering).
The problem is far from being solved. However, it's true that the pollution per inhabitant is much lower than in the Silicon Valley.