Even if 100% of the electricity was produced by coal, anytime you reduce the sources of pollution from millions of tailpipes to a few thousand power plants, you can easily regulate and install scrubbers to reduce the pollutants.
Unfortunately, many power plants in china ignore environmental regulations and don't install scrubbers (or have them but don't turn them on when officials aren't looking). China's pollution problem is primarily one of governance and rule of law.
A power plant that don't have a scrubber is likely still less polluting that 10000 power plants that have to weigh 150kg and that have an equally low likelihood of having any environmentally friendly implements.
Actually, auto exhausts in first tier cities that implement stricter emissions standards and disallow selling low quality gasoline are not that bad. The problem are the blue trucks that come in from the provinces at night that don't have good emissions equipment and are running on crappy gas. You could actually see the air quality get WORSE in Beijing after 11 pm, when few personal cars are on the road but the Hebei trucks start coming in.
Maybe, but in the US it ended up being quicker to get 95% of cars with catalytic converters then to get scrubbers on 95% of the coal plants. It seems power plant owners have more power to push against regulation than car owners.
Even if 100% of the electricity was produced by coal, anytime you reduce the sources of pollution from millions of tailpipes to a few thousand power plants, you can easily regulate and install scrubbers to reduce the pollutants.