From China Digital Space
暂住 (zàn zhù): temporary residence
The state of “temporary residence” refers to permission that some Chinese must obtain to work or live in 21 cities in China. Those in the cities without a temporary residence permit may be fined or deported. The temporary residence permits are of questionable legality because a similar national system of temporary residence permits has been abolished, and many scholars find cities’ current systems of temporary residence permits to be unconstitutional. However, notable among those cities that retain the system of temporary residence permits are Beijing and Shanghai, which claim the permits are necessary to impose order. Some cities have changed the name of the permits from “temporary residence permit” to “residence permit” while retaining the same basic system.