Some of those ghost cities claims are false. Some claims of 'ghost-city' are using obsolete photos(, e.g. the Florentia Village in Wuqing, Tianjin was falsely labeled ghost shopping malls in an io9.com article where you can hardly find a parking lot available on holidays).

Those cities are getting more and more popular because more people migrated from rural areas to these new urban areas, the amount of migration is huge.