The rapid urban population surge of the 60s driven largely from migration with resultant massive unauthorized city expansion provided challenges in finding effective housing interventions. Upgrading programs became widespread despite high monetary and spatial costs. This brief overview focuses on a mimic of the informal housing process which offered a direction for policy, adopted in the 70s by development agencies worldwide and known as ‘site and services’.
At the UN Habitat website he talks about these issues. View the talk here. Or watch it below.