https://gga.org/ghost-cities-africas-moving-in/

They're otherwise occupied. By Chinese. And elites. They're shitholes. Literally lots of condos. Mostly tucked away. The thing about them is simple, a real estate scam. They need somewhere to invest into so they make a ghost city. In China it devalues if people move, so instead they're empty. Although there is possibly other nefarious reasons to them. Optics, disguise, who really cares. In Russia many were abandoned infrastructure of soviet era operations military or resource, turning into ghost towns as operations ended, many blight the terrain, and some have much smaller populations within.

Infact there are a few globally. Asia in various nations. Russia. China. Africa. Possibly even South America. The reason to them is otherwise investment. But some are also of strategic importance.