“Lung washing tours” are the new thing in Chinese tourism. Smog is driving mainland tourists into novel migration patterns to escape the worst days of autumn, when the air stinks of coal and the other side of the street might just as well not be there.

Around the time Presidents Xi Jinping and Barack Obama were congratulating themselves on battling climate change in Beijing, I decided to drive five hours to a place near the very end of the Chinese earth, just to get a breath of fresh air.

It was my second lung-based tour in six weeks. In late September, I took two aircraft, a bus, a Jeep and a camel to get to a spot where I could safely savour the blue skies of Mongolia – in the middle of the desert, living in a yurt with nomads. I take this smog tourism thing quite seriously.