Agriculture is the mainstay of the Malagasy economy. Land is used for the cultivation of rice and other crops, raising of zebu and other livestock, the fabrication of bricks, and other traditional livelihoods. Access to land is guaranteed and protected by law for every resident of the city. The CUA manages requests to lease or purchase land, but demand dramatically outstrips supply, and much of the unallocated land fails to meet the requisite criteria for parceling, such as land where floodwater runoff is diverted. Much of this marginal land has been illegally occupied and developed by land-seeking residents, creating shantytown slums in pockets throughout the lower portions of the city. This uncontrolled development poses sanitation and safety risks to residents in these areas.