Suburbanisation is a process that occurs in urban areas alongside urbanisation, counter-urbanisation and urban resurgance. As people's prosperity increases, they search for a higher quality of life away from crowded and polluted areas in the inner city. Suburban areas which are more rural offer these factors, and so people move en masse to them out of the city center. In term the suburbs themselves grow physically, economically and socially. This is the process of suburbanisation. The process is in line with the concentric zone urban form model.