[throwmeaway33]

Smog != C02 People keep treating the two as if they're the same. They point at Beijing and think global warming.

Having more efficient power-plants, catalytic converters on cars, filtration, less use of coal, and more advanced engines in general leads to more complete combustion and less smog (less CO too).

I'm sure Beijing has lots of cars and people, but so does for instance NYC , and they don't have the same smog problems.