The Lower Ward is the home of Sigil's working class. It is hard to breathe there, polluted as it is from the smoke of industry and smoke from the many portals to the Lower Planes found in this part of the City of Doors. Smog, acid rain, and respiratory diseases are common.
Long before the Great Upheaval, the ward was known as the Prime Ward, as the Sodkillers and Incanterium would force natives of the Prime Material Plane to inhabit the ghettos of this district. A heavily scarred hero used an artifact known as the Shadow-Sorcelled Key to open all the portals to the Lower Planes at once, filling the ward with fiends of all sorts. The ward was devastated, but it was never again used as a Prime ghetto. Its name was changed to reflect the nature of its portals since that incident.