The United Nations World Cities Report 2026: The Global Housing Crisis: Pathways to Action may lay claim to be the most important housing report ever produced. It finds that the scale of global housing inadequacy affects around 42 percent of humanity. This has never previously been measured.

Approximately 3.4 billion of the world’s 8 billion population lack access to secure, safe, and adequate housing. Housing inadequacy encompasses insecure tenure, overcrowding, exposure to environmental hazards and a lack of access to basic services such as water, sanitation, power and waste collection. More than 1.1 billion people live in informal settlements and slums, the highest number ever, up from 201 million in 2010.

UN-Habitat describes the crisis as driven by rising housing costs, limited supply, widespread displacement, inadequate grading of existing homes and informal settlements and the growing impact of climate change.