Heatwaves in India: Causes, Impacts, Heat Action Plans & Climate Risks

India is witnessing early and intense heatwaves in April 2026, with temperatures crossing 40°C in several states.

• The India Meteorological Department has issued heat alerts in central and south India, including in Vidarbha, Chhattisgarh, Odisha, Telangana and Kerala.
• Status of Heatwaves In India
  • A World Bank report in November 2022 warned that by 2030, over 160-200 million people across India could be exposed to lethal heat waves annually.

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About Heat Wave

• About: A Heat Wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer months from March to July usually in the North- Western belt of India.
• Criteria by Indian Meteorological Department (IMD):
  • Maximum Temperature Condition : A station should record at least 40°C for Plains and at least 30°C for Hilly regions
  • a) Based on Departure from Normal
    • Heat Wave: Departure from normal temperature  is 4.5°C to 6.4°C 
    • Severe Heat Wave:  Departure from normal temperature of the station is more than 6.4°C
  • b) Based on Actual Maximum Temperature
    • Heat Wave: When actual maximum temperature ≥ 45°C
    • Severe Heat Wave:  When actual maximum temperature ≥47°C
  • If the above criteria met at least in 2 stations in a Meteorological sub-division for at least two consecutive days and it declared on the second day.

How do Heatwaves are formed?

• Persistent high-pressure system: Sinking air compresses and warms, preventing cloud formation.
• Clear skies: Maximum solar radiation reaches the Earth’s surface, causing continuous heating.
• Dry soil conditions: Reduced evaporation lowers natural cooling and raises land temperature.
• Hot and dry winds: Winds like the loo intensify already high temperatures.
• Urban Heat Island effect: Concrete surfaces and low green cover make cities hotter than nearby rural areas.
• Climate change: Rising global temperatures increase the frequency and intensity of heatwaves.

Reason for Current Heat Waves/ High Temperatures (2026): The following primary factors are driving the current extreme heat:

• Increasing Intensity and Spread of Pre-Monsoon Heatwaves: Pre-monsoon heatwaves are a regular feature in India, but their frequency, duration, and spatial extent are increasing.
  • They are now arriving earlier (April instead of May–June) and covering larger regions simultaneously.
  • This trend reflects broader climate change patterns, leading to prolonged exposure to extreme heat and higher risks to health, agriculture, and livelihoods.
• El Niño Effect: Warming in the Pacific Ocean weakens the Indian monsoon, leading to higher temperatures.
• Weak Western Disturbances: The absence of winter and spring rainfall has removed a natural cooling effect.
• Weak Convective Currents: A lack of local air rising and condensing into clouds has prevented natural afternoon cooling.
• Urban Heat Islands: Concrete and asphalt in cities trap heat during the day and fail to release it at night, keeping urban areas hotter than surroundings.
• Wet Bulb Temperature: A deadly combination of high heat and high humidity that prevents sweat from evaporating, making even 35°C lethal.

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What are Heat Action Plans (HAPs)?

• Heat Action Plans are early warning and response strategies designed to reduce the impact of extreme heat on human health and livelihoods.
• They are implemented at city, district, and state levels.
• Guided by agencies like the National Disaster Management Authority and inputs from the India Meteorological Department.
• Key Components of HAPs
  • Early Warning Systems: Heat alerts and forecasts
  • Public Awareness Campaigns: Advisories on hydration, avoiding peak heat
  • Health System Preparedness: Cooling centres, hospital readiness
  • Inter-agency Coordination: Between health, labour, and disaster departments

Issues with Current Heat Action Plans (HAPs)

• Reactive Approach: Heat Action Plans largely adopt a reactive approach, focusing on short-term emergency measures such as alerts and advisories rather than long-term prevention.
  • For Example: The Election Commission of India extended polling hours during elections to address heat exposure, reflecting a temporary adjustment instead of structural planning.
• Inadequate Funding: HAPs suffer from insufficient and non-dedicated funding, constraining long-term adaptation initiatives.
  • Several cities lack funds for interventions like cool roofs, water stations, and urban greening.
• Neglect of Informal Workers: There is a lack of enforceable heat-safety regulations for workers in the informal sector, increasing their vulnerability.
  • Construction and agricultural workers continue working during peak heat hours without legal protection or mandated rest periods.
• Lack of Urban Regreening: Cities like Delhi have lost significant green cover, worsening the Urban Heat Island effect.
  Urban areas can be 4–7°C hotter than nearby rural regions due to lack of trees and green spaces.
• Weak Institutional Coordination: Multiple agencies (health, disaster management, urban bodies) work in silos, leading to poor implementation of HAPs.
  • For example, lack of coordination between municipal bodies and health departments delays timely response during heatwaves.
• Limited Data and Early Warning Systems: Many cities lack localized, real-time heat data and ward-level risk mapping.
  • This results in generalized advisories instead of targeted interventions for high-risk groups and areas.

Impacts of Rising Heatwaves in India

• Night-time Heat Stress and Healthcare Burden: Warmer nights also delay physiological recovery, increasing the local health-care burden.
• Coastal Vulnerability and Urban Heat Island Effect: Local conditions in coastal areas, in particular, could be worse due to humidity and the urban heat island effect. 
• Increased Cardiovascular Mortality Risk: Persistently high heat is linked to a significantly higher risk of death from cardiovascular causes.
• Loss of Labour Productivity: Some 247 billion work-hours were lost in 2024 to heat, according to The Lancet Countdown Global Report, with workers in construction and agriculture the most affected. 
• Agricultural Stress and Food Security Concerns: Heat stress is an ongoing concern for farmers during the rabi harvest. Hot weather accelerates crop maturity, threatening food security and feeding inflationary pressure.

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Way Forward

• Columbia Coalition: India is encouraged to join this group of 50+ countries to access climate adaptation finance, technology transfer, and support for moving away from fossil fuels.
• Mobile Health Units: Deploy mobile clinics in heatwave-prone areas to provide on-site treatment for heatstroke, dehydration, and related illnesses
  • Cities like Ahmedabad have used outreach vans during extreme heat to reduce hospital burden and avoid long travel for vulnerable groups.
• Urban Re-greening: Promote mandatory tree plantation, green roofs, cool roofs, and permeable pavements to reduce surface temperatures and the Urban Heat Island effect.
  • Hyderabad has implemented cool roof programs, lowering indoor temperatures by 2–5°C in low-income housing.
• Heat-Safety Legislation: Enact laws mandating rest breaks, shaded worksites, access to water, and rescheduling of work hours during extreme heat.
  • States like Odisha restrict outdoor work during peak afternoon hours, reducing heat-related illnesses among laborers.
• Early Warning Systems & Heat Alerts: Develop localized, real-time heat forecasts with ward-level alerts to warn people in advance.
• Incorporation of Nature-Based Solutions: There is a need to focus on integrating nature-based solutions such as strategic placement of green spaces and the development of blue infrastructure into HAPs to mitigate the impacts of extreme heat.
• Accountability and Transparency: Create an online national repository of HAPs that is regularly updated and tailored to regional needs to improve transparency and accountability in heatwave management.

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