Rich Chinese cities are suffocating poor ones

The smog in Beijing was once so thick that a local brewery began selling a bitter beer called the “Airpocalypse”, which was cheaper on polluted days. These days fewer people are chugging a discounted brew. Last year Beijing saw only two days of very severe smog, according to the government’s method of measuring—down from 58 in 2013. The prevalence of a particularly dangerous class of pollutants called PM2.5, which comprises specks of dust and ash small enough to enter the bloodstream through the lungs, has fallen by two-thirds over a decade. Though levels are still well above what the World Health Organisation deems safe, city officials are proud of the progress they have made.