pajeets transformed their homeland into a polluted bio-hazard zone incapable of sustaining non-pajeet human lifeforms.
pajeets deliberately overloaded their own exposure to filth and contamination over millennia to reach a tolerance comparable to no other human race.
pajeets are spreading out of their safe-continent all over the world and terraforming the environment wherever they reach to only be capable of supporting them.
from an evolutionary standpoint pajeets are the ultimate lifeform.