slums

Slums are densely populated urban settlements characterized by inadequate housing and a lack of basic services. Definitions vary, but common features include insecure tenure, overcrowding, and limited access to clean water, sanitation, electricity, and durable housing. Buildings are frequently poorly constructed and vulnerable to fire, flooding, and other hazards. Slums occur in cities around the world and are often linked to rapid urbanization, poverty, and housing market constraints. They are known by regional terms such as shantytowns, informal settlements, squatter settlements, favelas, or kampungs.

Causes include rapid rural-to-urban migration, insufficient affordable housing, weak land-use planning, and policy gaps that exclude low‑income residents from formal housing markets. Slums arise where property rights are unclear, utilities are unaffordable, or land tenure is insecure.

Impact and living conditions: Residents face higher health risks, including infectious diseases and respiratory problems, and have limited access to healthcare and formal employment. Educational and social services are often harder to obtain, and households are vulnerable to eviction, natural hazards, and economic shocks.

Responses: Urban upgrading programs seek to improve water and sanitation infrastructure, housing quality, roads, and security of tenure, ideally through community participation. Other approaches include expanding affordable housing, inclusive zoning, and land-use planning reforms.

Measurement and context: Indicators used by international agencies assess access to water and sanitation, adequate living space, and tenure security. Globally, slums are concentrated in rapidly urbanizing regions of Asia, Africa, and Latin America, with numbers varying by definition and data source.