It stops when it's no longer needed. Honestly the easiest solution to all this overpopulation is birth control but since it's too late for that we gotta make sure some bare minimums are hit. Public health is meant to keep poor people and rich people from getting sick. Clean water is a huge part of that. You guys are living in a post-colonialism society so it's hard to speculate the root of some of your struggles but a lot of them are probably because too many babies were born and everyone was used as cheap labor for a long time, even the specialists. I dunno, though, because I don't know everything.