How have the courts treated the issue of blighted areas in the context of urban development?

In Redevelopment Agency v. Hayes, 1954, 122 Cal.App.2d 777, 796-797, 266 P.2d 105, we pointed out that blighted areas [195 Cal.App.2d 595] range the whole spectrum of social and economic interests of a community, affecting the health, safety and general welfare of the people of the community. Such interests are vital to the community or municipality. The interests are no less specific by being multiple. San Francisco, the donee of the power, has a preexisting, coexisting, and continuously subsisting interest in such matters which are the subject of the power, as well as a monetary interest.