The graphic above is a snapshot of air pollution at a particular moment in time: circa 11:30 AM (Beijing time), 17 degrees Celsius in Kunming, in mid-March, 2016.
However, you'll notice that Kunming is actually less polluted than many of the surrounding cities, at least at this moment in time. Remarkably, air-pollution in 西雙版納, 德宏, and many other (small) cities has caught up with Kunming, and has even exceeded it.
I wonder if Kunming has upgraded its power-plants to take some measures to ameliorate air-pollution that haven't yet reached the smaller cities. Those smaller cities are often presented to tourists as offering cleaner air than the regional capital; but, at least for the moment, that seems to be untrue.