Before opening up its economy in 1978, China had strict controls on migration from rural to urban areas
These controls were part of the permit (hukou) system, in which welfare benefits such as housing, education, and education were tied to a person's place of birth
As China moved towards a market economy, cheap rural labor helped fuel the country's growth and constraints on migration were reduced, however the restrictions on household registration of the hukou stayed the same, so migrant workers became outcasts without access to any state benefits or protection, despite Chinese laws enshrining "equal rights” for all