In scorching summer, warmer nights are a public-health challenge

📌 Summary:

• Context: Indian summers traditionally cooled at night, allowing the body to recover from daytime heat stress; this pattern is now changing as nights become uncomfortably hot, especially in low/middle-income housing without AC
• Core argument: Warmer nights are an emerging public-health crisis demanding architectural, urban-planning and policy responses — emergency-only Heat Action Plans (HAPs) are inadequate
• Causal chain — why warmer nights cause harm: (1) Sustained nocturnal heat blocks bodily recovery from daytime stress → cumulative cardiac strain (2) Worsens existing illnesses — respiratory disease, kidney ailments, hypertension (3) Urban heat-island effect: replacement of natural landscapes with concrete/asphalt/glass + shrunken air corridors trap heat → night temperatures stay high (4) Lack of AC in low-income housing compounds exposure of vulnerable groups
• Key data:
  • Climate Trends (Delhi) study in Chennai medium/low-income units: peak NIGHT temperature was nearly equal to peak daytime
  • Harvard Salata Institute White Paper (April 2026): ~38 crore Indian workers exposed to heat; adaptation policies "deeply unequal"
• Vulnerable groups: elderly, children, outdoor workers — street vendors, construction workers, gig-economy workers
• India's specific vulnerability: dense urban concrete sprawl + asymmetric AC access + heat-related morbidity is under-reported and poorly documented
• Critique of existing response: Several states/cities/districts have HAPs (early-warning, advisories, cooling centres) but quality is uneven; many lack dedicated funding & enforcement, focus on emergency response, ignore long-term adaptation, fail to identify most vulnerable
• Solutions proposed:
  • Building designs that prioritise ventilation and energy efficiency
  • Public policy nudges to industry for cooling solutions for low-income households
  • Integrate heat resilience into urban governance (zoning, land-use, materials)
  • Better documentation and reporting of heat-related morbidity

🎯 UPSC Relevance: GS2 Governance/Health — health systems & vulnerable groups; GS3 Environment — climate adaptation, urban resilience; GS3 Disaster Management — heatwaves

📝 Prelims Facts:

• Heat Action Plan (HAP): first major one in India was Ahmedabad's HAP (2013) after the 2010 heatwave
• Heat-island effect: urban areas remain warmer than surrounding rural areas due to anthropogenic heat & material absorption
• NDMA issued National Guidelines on Heat Wave (2019)

🔑 Key Term: Urban Heat Island (UHI) — Phenomenon where built environments stay warmer than surrounding rural areas due to heat-absorbing materials, low vegetation, and waste heat from buildings and vehicles