What exactly would a "rust belt" region be in the Chinese context? There's not much to be rusting yet...
Also, is there any explanation for the apparent belt of poorer inland provinces running from Shanxi to Jiangxi, between the wealthy coast and a second belt of wealthier provinces to their west? Were they "leapfrogged" in the spread of industry into interior China in favor of places further inland? Geographical disadvantages? Poor natural resources?
I know relatively little about the economic geography of China-- or its geography in general. (It doesn't help that so many of them have confusingly similar names.) Still, I never fail to be surprised when reminded of Inner Mongolia's apparently vast wealth. I can only assume that the place is highly unequal, although it's an assumption grounded purely in intuition. One also wonders who the leftists are in Xinjiang. They can't possibly be the locals.
I'd ask how they were able to collect such data in the first place, but I imagine the answer could be found in the linked document. Alas, I'm too tired to read it now-- maybe later.
The northeast states have had a decent amount of old communist industry that isnt aging well.