Discuss why night-time warming poses a greater governance challenge than daytime heat in India's disaster management framework.

A heatwave in India is declared on daytime maximum temperature, yet IMD's Core Heatwave Zone study (1961–2020) shows minimum temperatures rising at about 0.21°C per decade — faster than daytime warming [1]. This mismatch between the science and the statute is the heart of the governance problem.

The trend is real and measurable

• Over the CHZ, heatwave frequency rose ~0.1 day/decade and duration ~0.44 day/decade, both statistically significant [1].
• The Ministry of Earth Sciences has attributed this rising frequency and intensity of extreme heat to global warming [2].

A definitional blind spot in triggers

• NDMA/IMD declaration criteria rest on departure of the maximum temperature from normal — 4–5°C or an absolute 45°C threshold [3]. A hot night, however severe, generates no alert, no colour code, no trigger.
• Disaster response in India is trigger-driven; without a declaration, relief machinery, advisories and compensation norms do not activate.

Response machinery is daytime-calibrated

• IMD's heatwave guidance centres on avoiding exposure between noon and 3 p.m. [4] — advice irrelevant to overnight heat stress.
• Heat Action Plans, implemented by NDMA with 23 heatwave-prone States, largely schedule work-hour shifts, water points and shaded shelters for daylight hours [2].

Amplified and unequal human impact

• Warm nights deny the body its recovery window, raising cardiovascular and heat-stroke mortality.
• Urban heat islands keep built-up areas warmer after sunset, hitting informal settlements and outdoor workers who lack cooling and ventilation hardest.

Night-time warming is therefore not merely an additional hazard but a systemic gap: it is faster-growing, unmeasured by existing triggers, and unaddressed by existing responses. Incorporating minimum-temperature thresholds into heatwave criteria, extending Heat Action Plans to night shelters and cooling centres, and mapping urban heat islands would align India's disaster framework with its climate reality — advancing both SDG-11 (sustainable cities) and SDG-13 (climate action).