Analyze the reasons why the U.S. population has migrated from the Northeast to the West and South in recent decades.

Reasons: Northeast of the relocation area: 1. It is located in the old industrial area of ??the Northeast, the urban layout is unreasonable, the development of heavy industry is slow, employment problems are prominent, and land prices are rising. (Economic factors)

2. The city is seriously polluted and uninhabitable. (Environmental factors)

3. The climate conditions in the northeast are poor and it is a temperate continental climate.

The west and south of the relocation areas: 1. These areas are mostly emerging high-tech zones with less pollution, better urban environment, and better employment conditions.

2. Most of the migrant population are elderly people pursuing a comfortable living environment. The southern part has a humid subtropical monsoon climate. 3. The migration of young people pays more attention to the reasons of work and economic development.