(From our trip in April 2018)
After a huge sleep because yesterday was epic and exhausting, we were up and out the door for another day of torture sightseeing. A lot of the big cities in China, and I guess all around the world where there is lots of pollution, work on an air rating system. I am not a Rhodes Scholar on the subject but the lower the air rating for the day the better. The higher the air rating, the “abort abort, don’t go out, build a bunker and live underground for 50 years while we try and fix the problem” alarm sounds in people’s heads.