From the story...

“Living here takes a decade off our lives,” sighs our taxi driver, looking into the black smog ahead. We are in the town of Gongwusu, where Ningxia province meets Inner Mongolia. The driver often takes motorway 108 or 109 to destinations on either side of the border. “Everywhere the sky is full of black fumes, like storm clouds. You can’t see the sun; even in the daytime you need to put your headlights on.”