The great thing about air pollution is that you can see it. After years of ignoring the thickening smog around them – or dismissing it as an inevitable consequence of rapid growth – more and more Chinese are clearly worried. Last year’s “airpocalypse” was a turning point. PM2.5 fine particulates reached levels 70 times those considered safe in the west. Dangerously high levels of smog returned last month. In recent years there have been public protests against chemical factories and toxic waste spills throughout China. Even parts of the state media have taken to reprimanding local officials for failing to meet their own clean-up targets.

There are tentative signs too that President Xi Jinping’s administration is more serious about the problem. It appears to have concluded that pollution is a potential cause of mass discontent. Decreasing pollution also fits with its policy of improving the quality of growth by rebalancing the economy towards consumption. Mr Xi has let it be known that local officials will from now on be judged not purely by economic growth but also by improvements to the environment. If this is implemented, it marks progress. The government is also demanding real-time data from 15,000 heavily polluting factories.

In his first year in office, Mr Xi has consolidated power and driven through an anti-corruption campaign with great ruthlessness. He could plausibly do the same against pollution. Yet there are serious limits to what can be achieved. First, the use of coal, the biggest cause of bad air quality, will almost certainly increase, not diminish. True, China is planning 28 nuclear power stations to add to the 20 already in operation. Moreover, it intends to step up use of gas and hydroelectric power, itself not exactly environmentally cost-free. Even so, China’s main coal body is projecting a near-40 per cent jump in use by 2020.