What is the symbolic role of the image of darkness in Alas Babylon

This is a story about a nuclear holocaust. There is darkness both figuratively and literally.

Darkness in nearly all literature represents that which is low, inherently evil, and "bad." In Alas Babylon, we see the destruction of that which is civilized and thus more like a time in earlier history often characterized as the Dark Ages. Darkness indicates a descent into savage behavior and perhaps emphasizes the worst parts of humans at their lowest. We do not expect anything to happen in darkness (either figurative or literal) that is good or uplifting. We can only expect the worst in the dark situations.