I'd presume it's like the Soviets, where moving cities required permission. https://en.wikipedia.org/wiki/Propiska_in_the_Soviet_Union https://en.wikipedia.org

I'd presume it's like the Soviets, where moving cities required permission. https://en.wikipedia.org/wiki/Propiska_in_the_Soviet_Union https://en.wikipedia.org/wiki/Propiska_in_the_Soviet_Union