Por que é possível viver em Hiroshima e Nagasaki, mas não em Chernobyl?

https://brasilescola.uol.com.br/historiag/bombas-atomicas-hiroshima-nagasaki.htm
https://brasilescola.uol.com.br/historia/chernobyl-acidente-nuclear.htm
https://www.bbc.com/portuguese/noticias/2015/08/150808_hiroshima_nagasaki_chernobil_rm#:~:text=Ou%20seja%2C%20a%20radia%C3%A7%C3%A3o%20inicial,Chernobyl%20volte%20a%20ser%20habit%C3%A1vel.
https://gizmodo.com/why-can-people-live-in-hiroshima-and-nagasaki-now-but-1451250877
https://canaltech.com.br/ciencia/por-que-hiroshima-e-habitavel-e-chernobyl-nao-183448/
https://g1.globo.com/mundo/noticia/2020/08/09/por-que-e-seguro-viver-em-hiroshima-e-nagasaki-mas-nao-em-chernobyl.ghtml
https://homework.study.com/explanation/why-is-chernobyl-still-radioactive-and-hiroshima-is-not.html