China is the world’s second-largest market for electric vehicles, and nouveau riche renminbi have poured into purchases of the Tesla model S, the coolest green motorcar on the block. For at least a decade, Beijing has been decanting subsidies into the creation of a homegrown electric vehicle industry, hoping to leapfrog conventional engines and go straight to world dominance of green car technology. And China’s air pollution problem is so big that it must, like the Great Wall, be visible from space. So selling electric cars here ought to be about as easy as selling protective face masks. But it’s not.