How many waves of immigrants have there been in the history of New China? What's the background? What's the problem?

From the founding of New China to the mid-1980s, our government implemented a planned economy system and a strict household registration management system, and the migration of population was mainly planned and organized. In order to develop inland and frontier areas, a large number of organized immigrants, such as technicians, college students, veterans, cadres and educated youth, moved to Northeast China, Inner Mongolia, Xinjiang, Qinghai and Tibet to support construction. This is policy-oriented immigration, which is helpful to stabilize the political power and restore the development of production at the beginning of the founding of the People's Republic of China. However, the educated youth's going to the countryside has also caused a waste of talents and affected the country's economic and social development and progress.

Another large-scale immigration was at the beginning of reform and opening up. This migration belongs to spontaneous migration. The state puts forward the policy of getting rich first and then getting rich, increasing policy and capital investment in coastal areas to attract the flow of talents. People from inland to coastal areas, from rural areas to cities, have promoted the flow of technology, promoted the effective utilization of resources and really promoted the great development of coastal economy.