Heatwaves in India- Explained Pointwise

Heatwaves in India are becoming more severe and frequent, posing serious health risks. The last 2 years recorded unprecedented temperatures, with over 57% of Indian districts now classified as heat-prone. IMD predicts a rise in maximum temperatures and more heatwaves in eastern and southern India in the coming days. India must stay prepared to handle these recurring heatwaves.

Table of Content

What are heatwaves? How are they defined in India? What is the status of Heatwaves in India? What are the factors behind the increase in Heatwaves in India? What are the impacts of Heatwaves? What are the challenges in addressing heatwaves? What steps have been taken by the government to address the issue of heatwaves? What should be the Way Forward?

What are heatwaves? How are they defined in India?

• Heatwaves: Heat waves are prolonged periods of excessively hot weather that can cause adverse impacts on human health, the environment, and the economy.
• Definition of Heatwave: In India IMD defines heatwave based on the following criteria:
  

  Physiography of regions	Plain: Maximum temperature recorded at a station is 40 degrees Celsius or more. Coast: Maximum temperature recorded at a station is 37 degrees Celsius or more. Hills: Maximum temperature recorded at a station is 30 degrees Celsius or more.
  Departure from Normal Temperature	Heat Wave: Departure from normal is 4.5°C to 6.4°C Severe Heat Wave: Departure from normal is >6.4°C
  Actual Maximum Temperature	Heat Wave: When actual maximum temperature ≥ 45°C  Severe Heat Wave: When actual maximum temperature ≥47°C

*Heat Wave is declared if above criteria are met in at least 2 stations in a Meteorological subdivision for at least two consecutive days.

What is the status of Heatwaves in India?

India has been affected by the Heatwaves since a long time. However, during the last few decades, due to increased instances of climate change, the impact of heat waves has also enhanced quite significantly.

• States like Rajasthan, Gujarat, Uttar Pradesh, Delhi, Haryana, Punjab, Madhya Pradesh have been affected the most by the Heatwaves.
• According to IMD, between 1981 and 1990 there were 413 heatwave days in India. However, the heatwave days have increased to 600 days between 2011 and 2020.
• The number of deaths from heat-related causes increased from 5,457 between 1981 and 1990 to 11,555 between 2011 and 2020.

What are the factors behind the increase in Heatwaves in India?

Heatwaves can be caused by a combination of natural and human-induced factors. The main causes are mentioned below:

NATURAL CAUSES

High Atmospheric Pressure Systems: Heatwaves occur when high-pressure systems stall over a region. These systems trap warm air near the Earth’s surface and prevent the normal movement of air masses, leading to prolonged periods of hot weather. Climate Variability: Natural climate variations, such as El Nino and La Nina events, influence weather patterns and increase the likelihood of heatwaves. For ex- During El Nino events, warmer ocean waters in the tropical Pacific lead to changes in atmospheric circulation and weather patterns. Drought and Dry Conditions: Prolonged periods of drought and lack of precipitation reduces the overall moisture of the soil, causing the land to heat up more quickly during heat waves. Changes in Wind Patterns: Shifts in wind pattern transports hot air from one region to another which intensifies heat waves in areas that are not typically prone to such extreme temperatures. Geography and Topography: Geographic features and topographical conditions also contribute to the development of heat waves. For ex- Landlocked valleys and regions surrounded by mountains trap hot air and lead to temperature spikes.

ANTHROPOGENIC CAUSES

Global Warming: The long-term increase in Earth’s average temperature, primarily driven by human activities such as burning fossil fuels, deforestation, and industrial processes, contributes to the frequency and intensity of heat waves. Urban Heat Island Effect: Urban areas with high population density, extensive concrete and asphalt surfaces, and limited vegetation tend to absorb and retain more heat, has created localized zones of higher temperatures. This phenomenon, known as the urban heat island effect, has intensified heat waves in cities. Rapid Land Use & Land Cover (LULC) Changes: Deforestation: The loss of green cover reduces evapotranspiration—the process by which plants release moisture into the air to cool the environment. Without trees, the sun’s energy goes directly into heating the ground. Wetland Encroachment: Many Indian cities have built over traditional water bodies and wetlands. These areas previously acted as “heat sinks,” absorbing heat and providing a cooling effect through evaporation. Air Conditioning: The widespread use of ACs in urban areas creates a feedback loop. AC units exhaust hot air into the streets, raising the ambient outdoor temperature for those without cooling. Vehicular & Industrial Emissions: Heat generated by internal combustion engines and industrial processes adds “sensible heat” directly to the lower atmosphere. Greenhouse Layer: A thick haze of pollutants (aerosols) can act like a blanket, trapping outgoing infrared radiation and preventing it from escaping into space at night.

What are the impacts of Heatwaves?

1. Impact on Human Health: Rapid rises in heat compromises the body’s ability to regulate temperature resulting in a cascade of illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia. When external temperature approaches 37°C, the human body struggles to release internal heat, resulting in heat stress affecting organs like kidneys, liver, and brain. Reducing hospital and emergency room burden improves health system efficiency.
2. Impact on Energy: Heatwaves increase the electricity demand for cooling purposes, leading to strain on power grids and potential blackouts.
3. Impact on the economy: Heatwaves disrupt economic activities, affecting productivity of workers and labourers, lacking the access to reliable electricity for cooling during heatwaves. According to an ILO study at 34°C, workers can lose up to 50% of their work capacity. Protecting outdoor workers ensures continuity in farming, construction, logistics, and industrial sectors. It reduces loss of working hours, safeguards GDP.
4. Social Equity and Justice: The impacts of heatwaves are disproportionately felt by the poor, women, elderly, and migrant workers, making heatwave mitigation a key element in addressing social inequities. For the affluent, heat is an inconvenience managed through private cooling; but for nearly 400million informal workers, it is a systemic violation of the right to life & a driver of ‘Thermal Justice’. For these individuals, even a small rise in temperature causes a significant drop in productivity & a corresponding loss of income.
5. Impact on Water Resources: Heatwaves exacerbate water scarcity issues in India due to drying up of water bodies and decrease in the groundwater table. This exacerbates the inter-state conflict over water. For ex- Cauvery water Dispute.
6. Climate Resilience and SDG Goals: Heatwaves are one of the most direct manifestations of climate change. Addressing them contributes to the global goal of mitigating climate change and reducing carbon emissions. Aligns with SDG 3 (Health), SDG 8 (Decent Work), SDG 11 (Sustainable Cities), and SDG 13 (Climate Action).
7. Impact on food security: The rise in heat waves increase the probability of droughts, enhance demand of irrigation water, which impacts agricultural production and increases food insecurity.

What are the challenges in addressing heatwaves?

1. Early and Unpredictable Onset of Heatwaves: Heatwaves are now starting earlier in the year, catching authorities and populations off-guard. In 2025, severe heatwaves struck North and Central India 20 days earlier than in 2024, before HAP protocols were activated.
2. High Vulnerability of the Informal Workforce: Nearly 75% of India’s workforce (~400 million), especially in agriculture, construction, and street vending, is directly exposed to outdoor heat. In Odisha and Gujarat, many daily wage workers continued working in peak heat hours due to lack of income alternatives or workplace protections.
3. 10% Trap: Since heatwaves are not currently on the Nationally Notified Disaster List, States are restricted by the ‘10% Trap’, where they can only utilize a small fraction of their State Disaster Response Fund for relief efforts.
4. Economic and Productivity Losses: As per ILO and World Bank estimates (2023) heatwaves have a tangible economic cost, including loss of 3–5% of GDP and up to 6% of annual work hours. In sectors like agriculture and construction, heat-induced fatigue reduced work output and delayed infrastructure projects in Rajasthan and Telangana.
5. Unequal and Disproportionate Impacts: Marginalized groups—women, elderly, migrants, and the urban poor—face higher exposure with fewer coping mechanisms. Migrant families living in tin-roofed shelters in Delhi reported extreme indoor heat and health issues during April 2024.
6. Partial and Uneven Implementation of Heat Action Plans (HAPs): While 140+ cities and 23 states have HAPs, many lack funding, inter-agency coordination, and local customization. A 2023 CEEW analysis found that only a handful of HAPs included cooling centres, outreach in local languages, or inter-departmental response mechanisms.
7. Insufficient Public Awareness and Risk Communication: Awareness about heatwave risks and protective behavior remains low, especially in rural and low-income urban areas. In Bihar, despite IMD warnings in 2024, many communities continued outdoor weddings and festivals in peak hours, leading to heat-related illnesses.

Read More- Protecting the most Vulnerable due to Increasing heatwaves in India

What steps have been taken by the government to address the issue of heatwaves?

Heat Action Plans	The Indian government has updated Heat Action Plans across 23 states, aiming to strategically combat and manage heatwaves.
Public Health Preparedness	The Union Health Ministry reviews the preparedness for managing Heat-Related Illnesses (HRIs) periodically indicating a proactive approach to address the health impacts of heatwaves.
Focus on Vulnerable Groups	The government initiatives prioritize protecting high-risk groups like children, pregnant women, the elderly, and people with chronic diseases.
Awareness Campaigns	About 100 districts have initiated campaigns to raise awareness about heatwave risks and precautions.

What should be the Way Forward?

1. Heatwaves as National Disaster: Accept 16th Finance Commission’s recommendation to include heatwave & lightening in the Notified National Disaster List for the 2026-31 period. Such a move would unlock the National Disaster Response Fund, bypass current spending restrictions, and convert early warnings from simple advisories into binding mandates for district admin.
2. Heat Index: Ministry of Labour & IMD must transit towards Heat Index – a metric combining temperature & humidity to reflect true human feel – as the primary legal trigger for declaring heatwaves. This is essential to ensure that coastal areas, which face the lethal combination of heat & humidity, are not at a disadvantage in national safety protocols.
3. Effective implementation of Heat Wave Action Plan: Effective implementation of the Heat wave action plan with the State playing a leading role and sharing responsibility with other stakeholders is now the need of the hour. Update HAPs in every State based on local vulnerability assessments. Include humidity, nighttime temperatures, and thermal comfort indexes for long term planning.
4. Improve Early Warning and Forecast Systems: Introduce Heat Health Alert (HHA) systems as in the UK. Use predictive analytics for work timing adjustments in schools, factories, and offices.
5. Build Heat-Resilient Infrastructure: Promote cool roofs, white rooftops, reflective paint, better urban ventilation, and green corridors. Adopt heat-resilient building codes and zoning laws.
6. Sustainable Cooling: Passive cooling technology like construction of ventilated buildings and the use of porotherm bricks, can be a vital alternative to address the urban heat island for residential and commercial buildings.
7. Heatwave Mitigation Plans: Heatwave mitigation plans which includes access to drinking water, oral rehydration solutions (ORS), shade at public places, flexible working hours in workplaces must be effectively designed and implemented.
8. Protect Informal Workers:
   • Allow staggered/shifted work hours.
   • Provide financial support and insurance for wage losses during heatwaves.
   • Govt must exercise its powers under Sec 23 of OSHWC Code (Occupational Safety, Health & Working Conditions) to notify binding heat safety rules – such as provision of specialized PPE (Personal Protective Equipment) as a non-negotiable employer obligation.
9. Creation of more Green Spaces: According to the UN, investment of US$ 100 million in street trees globally can bring 1°C temperature reduction. India must scale up its reforestation and tree plantation efforts. For ex- Haritha Haram project of Telangana Govt to increase the green cover in Telangana from the current 24% to 33%.
10. Adoption of energy efficient solution: The masses should be encouraged to adopt more energy efficient solutions like using desert coolers in place of air conditioners in dry areas.
11. Data-Driven Decision Making: Collect granular, real-time heat morbidity and mortality data. Map hotspots within cities to identify intra-urban heat inequality.
12. Encourage Behavioral and Institutional Change: Public awareness campaigns, climate literacy, and workplace heat safety protocols.
13. Long-Term National Policy: Integrate heatwave resilience in National Disaster Management Plan, Smart Cities Mission, and urban master plans. Incentivize tree plantation, wetland conservation, and urban greening.

Conclusion: The battle against heatwaves must move beyond token advisories and aim for science-based, people-centric, and equity-focused long-term planning. As the cost-effectiveness of heat adaptation is well-established, prioritizing this agenda is not only a climate responsibility but also a development necessity.
Hence, heat governance must be reimagined as a core component of the social contract where thermal safety is a non-negotiable mandate of constitutional justice.

Read More: The Hindu UPSC Syllabus: GS Paper 3: Environment – climate change GS Paper 1: Geography – Important Geophysical phenomena such as Heatwaves.