This one needs 3000 "room for new settlers". Since your settler total automatically fills, most people will be near or actually full. Therefore, it appears this quest require me to slaughter half my standing army in one suicide-run Quest after another. And to turn off the schools/universities to stop them repopulating while I do it. Then if I kill off enough, I'll spend massive amounts of resource and time re-training everyone when we are done. (I don't have anywhere near enough Building Licences to drop enough houses for 3000 new people.)
Is there a better way to do it than a complete massacre?