In theory, these INFONAVIT units go by the showy name of "subsidized social housing", and their theoretical function is to provide an affordable dwelling for working-class Mexicans. Based on Le Corbusier's pretentious bullshit about high-density urbanism and organization, these units exist supposedly to give thousands of Mexicans a place to live.
In practice, these places are dirty fucked-up holes of crime, poverty and social decay, packed to the limit with cholos, whores, crack dealers, wife-beating machos, and teenage couples. No self-respectable Mexican ever dares entering these dens of corruption, lest chances are they will get robbed, beaten up and gang-raped. This situation has gone so far, the term "INFONAVIT unit" is nowadays a synonym for "ghetto".