I visited China in 2014 and I have literally wondered out loud this morning whether air pollution has improved since then. I am gald to hear the answer is yes!
I've been visiting China every 1 to 3 years since 2014 and definitely in the last 4 years, on multiple visits, I've noticed that pollution is visibly lower. You can actually see the blue of the sky on most days. Everyone has noticed it. It's a massive change.