Urban disease refers to the influx of people into big cities, resulting in excessive consumption of their public service functions, resulting in traffic congestion, housing tension, air pollution and other problems. Some experts believe that when the urban disease is serious to a certain extent, the attraction of big cities will decline, people will no longer gather in big cities as before, and the urban disease will be reduced
The public services that big cities can provide cannot be replaced by small and medium-sized cities
as to radiate new vitality.