The City of Veil
Placed near most roads and streets are lamp posts that glow with the brightness of a torch. They are known as lamplights. These lamplights do not give off heat and are magically powered with arcane ash. This allows travel through parts of the city at night, allowing more business and activity to occur after the sun has set.
The dwarven and elven wards, as well as the poorer wards do not use as many lamplights as the arcane ash needed to power them is expensive. To them, the gold would be better spent on food. Plus, they can see in the dark better than humans.
Obviously, the more wealthy the area, the more lamplights.