The daily influx of people into the city provides the skilled labor force that allows Makati to handle the service requirements of domestic as well as international transactions; it also serves as the base of a large consumer market that fuels the retail and service trade in the city. At the same time, however, the large tidal population flows exert pressure on Makati's environment, services, and utilities, most noticeably causing large traffic volumes along the major road corridors leading to the city as well as within and at the periphery of the central business district.