Chinese economic reform
Since the Chinese economic reform from the late 1970s exacerbated uneven regional development, while Uyghurs have migrated to urbanizing Xinjiang cities, some Hans have also migrated to Xinjiang for independent economic advancement. Increased ethnic contact and labor competition coincided with Uyghur separatist terrorism from the 1990s, such as the 1997 Ürümqi bus bombings.