人口不足
The shrinking of urban populations indicates a changing of economic and planning conditions of a city. Cities begin to 'shrink' from economic decline, usually resulting from war, debt, or lack of production and work force. Population decline affects a large number of communities, both communities that are far removed from and deep within large urban centers. These communities usually consist of native people and long-term residents, so the initial population is not large. The outflow of people is then detrimental to the production potential and quality of life in these regions, and a decline in employment and productivity ensues.