Electricity is not clean or dirty per se, as it is only a method of energy transport (well, it is a bit dirty per se, since it has losses - which can obviously be discarded if it is used to connect clean production facilities and replace dirty energy production)
If I own a coal power station that powers 500 000 electric cars, one government inspector shows up and he says "No, no, no, you must install this scrubber, or we will close you down". So now I need a scrubber.
If I own one of the 500 000 diesel cars, the government cannot afford to send an inspector to examine my car, maybe they will ask the mechanic who services it to do their work, but I can trivially bribe him to turn a blind eye. So I can keep polluting.
If I own the coal plant, the government will make me build a tall chimney to pump the waste gases into the upper atmosphere and spread them out more, and of course I shan't build the plant on expensive city centre land, but further away.
But if I own just a car I can spew the waste gases out onto the street, and collectively they will be densest in city centres where the most people are because that's where they use their cars.
We'll know we've turned the corner when the hot spot on local pollution maps is always some big old power station not a city.
On the other hand, the personal car market is much more regulated, China demands relatively recent emissions equipment and have cracked down on dirty gasoline in many cities. This doesn’t apply to blue trucks, which are super polluting and use shitty gas from outside the city, but personal cars weren’t the major polluter like coal was.
So China made great strides in just banning coal and using NG for electric generation even though they don’t have much local supplies. Renewables will eventually help also, but they are generally far away from where they are needed (in western China, whereas everyone lives east). Now that coal is less of a problem, cars will eventually dominate, and probably already do in southern cities that don’t have indoor heating.
That said, China - and most of the world - is on an exponential growth curve for renewables right now. It will take a long time for the world to switch over to EVs, so we're better off starting now, regardless of the current emission profiles for electricity generation.
Cars are especially good for this, since they all need to use batteries and are parked for most of their lifetime. Peak power usage isn't as much of an issue with smart meters.