Very interesting documentary. Basically, chinese millionares are overinflating chinese housing markets to such a degree, that people growing up in specific areas can never afford building a house in the place they grew up.
Many houses are bought as an investment as well, and they sit empty, dulling neighbourhoods in the process.
Edit: Also, starting at Minute 15, it is explained that those millionaires on average only pay an income tax of 1400 dollars per year.