Since the late 1970s Chinese economic reform exacerbated uneven regional development , more Uyghurs have migrated to Xinjiang cities and 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
1997 Ürümqi bus bombings
1997 Ürümqi bus bombings
History of Xinjiang