Counterpoint - I returned to China (Beijing) last summer after 9 years and was honestly surprised how LITTLE it has changed over those 9 years, I was expecting big changes reading this tales about Shenzhen, but the reality is maybe only 1/4-1/3 of the cars on the road were EVs, there were pretty much none escooters, people still smoke in restaurants and yes, the air was for the most part perfectly fine, though this was really case in summer even before.

The most noticable change which puzzled me where those big boxes with slots in all restaurants and grocery shops, which are rental powerbanks.

Other than these hardly anything changed, policemen in police station smoked right under no smoking sign and in that half an hour in their office I inhaled more secondary smoke than in years in Europe combined. To their credit they were as laid back as policemen in my small home town. Beijing province border checks are more strict, but they still let us go without registered accommodation on weekend.

Oh yeah, out of dozens restaurants we frequented ONE fancy hot pot restaurant had robot bringing over plates.

Plus Taobao/Tmall seems replaced now with Pinduoduo with super cheap purchases (think double the Alibaba/factory price) including free shipping.

Mutianyu great wall is now fully mainstream, everyone (99%) now use cable car instead of hiking uphill, before it felt at least 50:50, people got lazy.

Ah yeah, everywhere you go you need to present passport and sometimes also book ticket in advance, so from tourist standpoint it's worse, before you could just show up same visit major sights in Beijing even without passport.

1/4-1/3 EVs is an underestimate for somewhere like Shenzhen (probably for Beijing too). It's going to be well over 50% there. And virtually all scooters will be electric.

You're right about the smoking, though. It's a massive problem.