From the Economist:

China’s goal is not just to replicate the boom of its coastal areas. It wants to tame Xinjiang, its wild western frontier. Since January 2000, when China launched the “great development of the west” (often referred to as the “Go west” policy), it has been clear that there is more to this than simply boosting growth in China’s economic backwaters. It is shorthand for a policy of tightening central control over remote, far-flung territories and assimilating them into China proper. Xinjiang (literally meaning “New Frontier”) was the most recalcitrant region of the lot.