Housing, or more generally living spaces,Ranasinghe ,WC and Hemakumara, GPTS(2018), Spatial modelling of the householders' perception and assessment of the potentiality to improve the urban green coverage in residential areas: A case study from Issadeen Town Matara, Sri Lanka, Ruhuna Journal of Science,Vol 9(1); http://rjs.ruh.ac.lk/index.php/rjs/article/view/174 refers to the construction and housing authority of houses or buildings collectively, for the purpose of Shelter (building)ing people —the planning or provision delivered by an authority, with related meanings. The social issue is of ensuring that members of society have a home in which to live, whether this is a house, or some other kind of dwelling, lodging, or shelter (building).Gwendolyn Wright, ''Building the Dream: A Social History of Housing in America'' (MIT press, 1983) Many governments have one or more housing authority, sometimes also called a housing ministry, or housing department.
The term informal housing can include any form of shelter or settlement (or lack thereof) which is illegal, falls outside of government control or regulation, or is not afforded protection by the state. As such, the informal housing industry is part of the informal sector. typically, the informal occupant or community will lack security of tenure and, with this, ready or reliable access to civic amenities (potable water, electricity and gas supply, sanitation and waste collection). Due to the informal nature of occupancy, the state will typically be unable to extract rent or land taxes.
The term informal housing is useful in capturing informal populations other than those living slum settlements or shanty towns, which are defined more narrowly by the UN Habitat as "contiguous settlement where the inhabitants are characterizes as having inadequate housing and basic services...often not recognised or addressed by the public authorities an integral or equal part of the city."
Common categories or terms for informal housing include slums, slum settlements, shanty towns, Squatting, homelessness and pavement dwellers.
Many cities in the developing world are experiencing a rapid increase in informal housing, driven by mass migration to cities in search of employment or fleeing from war or environmental disaster. According to Robert Neuwirth, there are over 1 billion (one in seven) squatters worldwide. If current trends continue, this will increase to 2 billion by 2030 (one in four), and 3 billion by 2050 (one in three). Informal housing, and the often informal livelihoods that accompany them, are set to be defining features of the cities of the future.Laquian, Aprodicio A. ''Basic housing: policies for urban sites, services, and shelter in developing countries'' (Ottawa: International Development Research Centre, 1983).