federal policies federal housing finance in particular have facilitated the development of higher quality houses yet have often failed to contribute to the development of better cities reforms to infonavit s practices thus form the basis upon which a more competitive sustainable housing and urban development model can be built first like many latin american countries mexico has a long history of informal or irregular housing development and a large share of the housing stock continues to be selfbuilt lacking legal titles or constructed outside the formal development process nearly onequarter of urban households live in informal settlements