The existence of a large population living in areas engaged in informal settlements, slums and areas of risk, motivated creation of public policies of social interest in ensuring the population a right to decent housing, securing land tenure, rescuing citizenship
and improved environmental quality.
The creation of Special Zones of Social Interest - ZEIS have their support the 1988 Federal Constitution, in Articles 182 and 183 of the City Statute and as provisional no. 2,220 of 04/09/2001, when worries about the question social and seeks to benefit the slum dwellers, subdivisions and housing through the legalization of the right to housing