It would preferably be something that will either last a fairly long time fifteen to twenty years perhaps, periodically and last at least some months between or last indefinitely. I do not require other species to be capable of survival though preferably at least some animals and plants should be capable of surviving as well. Assume a large amount of the human populace is capable of surviving regardless of the absence of other lifeforms.
I'm still working on the fine details of this world. But it is post apocalyptic as well as cyberpunk. Scifi clearly. Within these criteria there really isn't any other restrictions.