Every year, China burns as much coal as the rest of the world combined and, every year since 2009, more cars have been sold there than in any other country. This has left its cities choking on poisoned air and has been responsible for an estimated one million premature deaths a year.
But, since 2014, China has been waging a "war on pollution" and this campaign has begun to show results. Last year, levels of particulate pollution in Beijing dropped by more than 20 per cent over the previous year. The politics of this was obvious. The country's leadership was worried that its citizens simply wouldn't tolerate air so polluted that it can be difficult on some days in some cities to see through the soupy, acrid haze to the buildings across the street.