It is a seedy region. While Pluribus is overall a clean place with a law abiding population, a mega city of this size does have a criminal element. There are illegal immigrants from societies not Union members  Drug additcts, members of illegal groups, Non Cits and Drifts . These individuals gather in the Base Level district.
The Base Level is still far from lawless and not a real slum, but crime rates are high and murder is not as uncommon as elsewhere in the city.
 Immigrants that for one reason or the other can not legally immigrate.