Last week was a very bad week to be in Shanghai. We had the worst pollution here, ever, as far as I can gather. There are lots of different numbers thrown around, but pretty much everyone agrees that the PM2.5 count went above 500 last Friday (December 6, 2013). Just to put that “500″ in perspective:
WHO guidelines say average concentrations of the tiniest pollution particles – called PM2.5 – should be no more than 25 microgrammes per cubic …