Warmer Nights Emerge as a Growing Public-Health Challenge in Indian Cities

A growing body of research suggests that nights in many Indian cities no longer offer the relief from heat that they once did. A recent study by Climate Trends, a Delhi-based climate research organisation, monitored medium- and low-income residential units in Chennai and found that the peak night-time indoor temperature was not very different from the temperature people experience during the hottest part of the day. For households without access to air-conditioning, this means the human body gets very little time to recover from daytime heat stress.

Studies and clinical experience have linked sustained exposure to high temperatures with cardiac stress and the worsening of existing illnesses, including respiratory and kidney ailments. Heat-related illness and deaths are widely believed to be under-reported in India because they are recorded only when the immediate cause of death is direct heatstroke. The elderly, children, pregnant women and people in outdoor occupations — such as construction workers, street vendors, agricultural labour, sanitation workers and gig delivery workers — are particularly vulnerable.

Several Indian states, cities and districts have developed Heat Action Plans (HAPs) that include early-warning systems from the India Meteorological Department (IMD), public advisories, cooling centres and inter-agency coordination. However, their quality is uneven: many lack dedicated funding, enforcement mechanisms, and a longer-term focus on adaptation measures such as urban tree cover, cool-roof programmes, water-body restoration, and bioclimatic building design. The National Disaster Management Authority (NDMA) has been pushing states to upgrade their HAPs and to recognise heatwaves as a notified disaster category.

For exam aspirants, the issue connects climate change adaptation, the role of the IMD and NDMA, the “heat-island effect” in cities, occupational health, and the broader policy debate on climate finance for adaptation under the UNFCCC.