Legal basis: Article 4 of the Urban and Rural Planning Law of People's Republic of China (PRC) should follow the principles of overall planning, rational layout, land conservation, intensive development and planning before construction, improve the ecological environment, promote the conservation and comprehensive utilization of resources and energy, protect natural resources such as cultivated land and historical and cultural heritage, maintain local characteristics, national characteristics and traditional features, and prevent pollution and other public hazards, which is in line with regional population development and national defense. Construction activities in the planning area shall comply with the provisions of laws and regulations on land management, natural resources and environmental protection. The local people's governments at or above the county level shall, according to the reality of local economic and social development, reasonably determine the development scale, steps and construction standards of cities and towns in the overall urban planning and town planning.