Nekropoli

Lily climbed over the debris that clogged the street. Around her, there was silence, save for the occasional stiff shuffling around in an aimless haze. She struggled to breath in the heavy protective gear, the mask narrowing her vision to two small holes, but one look at the acid-eaten buildings and she knew to keep them on. The entire block was deserted, left to stiffs to handle.

Nekropoli are places so polluted, hazardous, or otherwise uninhabitable that all but the most desperate avoid it. Instead, the Nekropolis are left to undead to manage to work in, sometimes for days or weeks without human supervision, making them true homes of the dead. What causes a place to be designated as a Nekropolis varies, but they can be urban, rural, and most commonly industrial areas where conditions have gotten so bad that even breathing the air is.. Unadvisable.
Most have been deserted for some time, and some are ancient by modern standards. Entire mythologies have sprung up around these tainted places, and they are commonly depicted in film, radio, and literature - sometimes as merry little havens for sentient undead who live secret lives, far away from mortal eyes.
In reality, these crumbling places are so poisoned that even the undead struggle here. Industrial or even magical pollution, neglect and greed, human laziness all play their part in creating a Nekropolis. With enough corpses around to run whatever industry remains there, little incentive to clean up and restore the Nekropoli.
Some few find the Nekropoli to be convenient, if dangerous, places to lay low. Only the most implacable foe would chase their mark into a Nekropoli.

by Unsplash