Here’s the summary for the wikipedia article you mentioned in your comment:

Under-occupied developments in China were mostly unoccupied property developments in China, and frequently referred to as "ghost cities" or ghost towns. The phenomenon was observed and recorded as early as 2006 by writer Wade Shepard, and subsequently reported by news media over the decades. Although a feature of discourse on the Chinese economy and urbanization in China in the 2010s, formerly under-occupied developments have largely filled up.

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