Systematic Evidence Mapping of Heat Stress Adaptation Strategies in Informal Settlements in Asia and Africa

Rising global temperatures and rapid urbanisation have intensified heat stress exposure in informal settlements across Asia and Africa, where vulnerable populations face significant thermal comfort challenges due to inadequate housing conditions and limited adaptive capacity. This systematic evidence mapping study aims to identify, analyse and synthesise existing evidence on heat stress adaptation strategies implemented in informal settlements across Asia and Africa. A systematic search was conducted across Scopus and Web of Science databases using structured search strings related to heat stress, thermal comfort and cooling interventions in informal settlements in Asia and Africa. Data extraction focused on study characteristics, adaptation interventions, effectiveness measures in improving thermal comfort and reducing health risks, and barriers to implementation. The evidence mapping revealed diverse adaptation strategies, including reflective roofing, natural ventilation, air conditioning, tree planting, green walls and building modifications implemented by various actors such as communities, non-governmental organisations, local governments and international organisations. Effectiveness was primarily measured through indoor temperature reduction and instrumentation-based thermal comfort assessment. Financial barriers, particularly affordability issues, emerged as the most significant implementation constraint, followed by institutional barriers, including policy gaps and weak governance. While multiple heat stress adaptation strategies show promise for improving thermal comfort in informal settlements, implementation remains constrained by financial, institutional, social, technical and environmental barriers. This evidence mapping highlights critical research gaps and the need for context-specific, affordable and community-driven adaptation solutions tailored to the unique vulnerabilities of informal settlement populations.