Heatwaves in India: Causes, Impact, and Preparedness
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Heatwaves have become an increasingly severe issue in India, affecting millions of people and the economy. With rising global temperatures and climate change accelerating extreme weather conditions, the country is experiencing prolonged and more intense heatwaves. The India Meteorological Department (IMD) defines and measures heatwaves based on specific temperature thresholds. However, despite early warnings and Heat Action Plans, the impact on public health, livelihoods, and agriculture remains a significant concern. This article explores how heatwaves are defined, their causes, effects, and India’s preparedness to tackle them.
What is a Heatwave and How is it Defined?
- A heatwave is a prolonged period of excessively high temperatures over a particular region, surpassing the usual climate conditions of that area.
- The India Meteorological Department (IMD) categorizes a heatwave based on:
- Plains: When the maximum temperature reaches 40°C or more.
- Hilly regions: When the maximum temperature reaches 30°C or more.
- Coastal areas: When the temperature reaches 37°C or more with an anomaly of 4.5°C or more from normal.
- The severity of a heatwave is determined by:
- Heatwave: If the temperature exceeds normal by 4.5°C to 6.4°C.
- Severe heatwave: If the departure is more than 6.4°C or if the maximum temperature crosses 45°C.
- A heatwave is officially declared when two or more IMD observatory stations report such temperatures for at least two consecutive days.
How Does the IMD Measure Heatwave Conditions?
- The IMD maintains a network of surface observatories across India to monitor various meteorological parameters such as:
- Temperature
- Relative humidity
- Air pressure
- Wind speed and direction
- Heatwave monitoring is based on climatology calculated from historical temperature data spanning 1991–2020.
- Heatwaves in India typically occur from March to June, occasionally extending into July.
- Factors that worsen heatwave conditions:
- High humidity levels prevent the body from cooling through sweating.
- Elevated nighttime temperatures prevent recovery from daytime heat exposure.
- Regional variations exist in heatwave definitions. For example, what qualifies as a heatwave in Kerala may not be considered one in Rajasthan due to differing baseline temperatures.
Impact of Heatwaves on Public Health and Livelihoods
Heatwaves pose a serious threat to public health, particularly for vulnerable populations such as the elderly, children, outdoor workers, and those with pre-existing health conditions. The National Programme on Climate Change and Human Health reported over 48,000 suspected heatstroke cases in 2024, with 269 suspected deaths and 161 confirmed fatalities due to extreme heat.
- Health Risks
- Heat-related illnesses such as heat exhaustion and heatstroke can be fatal if not treated promptly.
- High temperatures can worsen cardiovascular and respiratory diseases, increasing hospitalizations.
- Prolonged exposure to heat can cause dehydration, kidney stress, and mental fatigue.
- Impact on Outdoor Workers
- Traffic constables, sanitation workers, construction laborers, and farmers are among the most affected groups.
- Many workers continue to toil in extreme conditions due to economic constraints.
- In Karnataka, the Mangaluru City Corporation considered changing work hours for sanitation workers, but practical implementation remains a challenge.
- Economic Consequences
- Businesses that rely on seasonal trends, such as winter clothing manufacturers, are struggling as shorter winters impact sales.
- Agriculture suffers massive losses, with crops like wheat and mangoes experiencing lower yields due to unseasonal heat.
- India is estimated to lose 5.8% of daily working hours by 2030 due to heat stress, reducing productivity in agriculture, construction, and industrial sectors.
Government Response and Heat Action Plans
To combat rising heatwave threats, the National Disaster Management Authority (NDMA), in collaboration with IMD and state governments, developed Heat Action Plans (HAPs) for 23 states and union territories. However, many of these plans remain underutilized or ineffective due to poor implementation.
- Challenges in Implementation
- Many local authorities lack awareness and coordination to execute these plans efficiently.
- Funding constraints prevent infrastructure development for heat shelters and cooling centers.
- Lack of real-time data makes it difficult to track and respond to emerging heat-related emergencies.
- Successful Models
- Ahmedabad became South Asia’s first city to implement a Heat Action Plan in 2013, setting a precedent for other cities.
- Ballari in Karnataka introduced shorter work shifts for traffic police, demonstrating that small changes can protect vulnerable workers.
- The India Cooling Action Plan (ICAP) aims to reduce cooling demand and enhance energy efficiency by 2037-38.
- Possible Solutions
- Decentralized decision-making based on scientific data to identify high-risk areas.
- Increased public awareness campaigns on heat protection measures.
- Stronger enforcement of worker protection policies, including mandatory rest breaks and access to cooling shelters.
- Urban planning reforms to mitigate the urban heat island effect, such as planting trees and using heat-resistant building materials.
The Role of Climate Change in Intensifying Heatwaves
Climate change is a major driver behind the increasing frequency and intensity of heatwaves in India. Rising greenhouse gas emissions have led to global warming, altering weather patterns and making extreme heat events more severe and prolonged.
- Scientific Observations
- 2024 was the warmest year in India since 1901, with February 2025 setting new records as the hottest February in 125 years.
- The Intergovernmental Panel on Climate Change (IPCC) warns that extreme weather events, including heatwaves, are set to increase due to human-induced climate change.
- The Centre for Science and Environment (CSE) reported that 255 out of 274 days in 2024 saw extreme weather events in at least one region of India.
- The Urban Heat Island Effect
- Cities are heating up faster due to increased concretization, which absorbs and retains more heat.
- Lack of green spaces and widespread use of glass-facade buildings contribute to higher energy consumption for cooling.
- In Delhi, night-time temperatures remain significantly high, increasing thermal discomfort for residents.
- The Role of Oceanic and Atmospheric Phenomena
- El Niño and La Niña cycles affect monsoons and seasonal heat patterns.
- The 2023–24 El Niño was one of the strongest on record, leading to higher-than-normal summer temperatures.
- Scientists predict that future El Niño events will be more frequent and intense, worsening India’s heat crisis.
- Consequences of Rising Heat
- Increased heat triggers more wildfires, droughts, and water shortages, leading to cascading effects on food and water security.
- Warming oceans increase cyclone activity and unpredictable monsoon patterns, causing extreme rainfall in some regions while leaving others in drought.
- Public health risks escalate, with heat-sensitive diseases like dengue, malaria, and respiratory illnesses becoming more prevalent.
Economic and Agricultural Impact of Heatwaves
The economic consequences of extreme heat events are far-reaching, affecting multiple sectors, particularly agriculture, industry, and infrastructure.
- Agriculture and Food Security
- Heatwaves reduce crop yields, affecting staple grains like wheat, rice, and maize.
- Farmers in Maharashtra’s Alphonso mango belt have reported up to 70% lower yields due to premature flowering and fruit drop.
- Heat stress on livestock reduces milk production, impacting the dairy industry.
- Impact on Water Resources
- Reservoir levels in northern India dropped to 28% of capacity in early 2025, raising concerns about irrigation and drinking water availability.
- Glacier retreat in the Himalayas threatens the long-term water security of millions.
- Groundwater depletion due to excessive extraction for cooling and irrigation worsens water stress.
- Industrial and Energy Challenges
- Rising temperatures increase electricity demand for cooling, leading to power shortages and blackouts.
- Heat stress reduces labor productivity, particularly in construction, manufacturing, and service sectors.
- The textile industry in Ludhiana is struggling as shorter winters reduce demand for woolen clothing.
- Inflation and Economic Disruptions
- Food price inflation rises due to lower crop yields and supply chain disruptions.
- The Reserve Bank of India (RBI) has raised concerns about inflationary pressures due to extreme weather conditions affecting food and fuel prices.
- Economic losses due to extreme heat events could cost India 5.4% of its GDP by 2030.
Policy Measures and Preparedness for Heatwaves
Despite the increasing frequency of heatwaves, India’s policy response has been inadequate, with many heat action plans either lacking proper implementation or failing to reach vulnerable populations. However, certain policies and interventions have shown promise in addressing the crisis.
- National and State-Level Heat Action Plans (HAPs)
- The National Disaster Management Authority (NDMA), in collaboration with state governments and IMD, has developed Heat Action Plans (HAPs) for 23 states and union territories.
- Ahmedabad was the first city in South Asia to introduce a Heat Action Plan in 2013, and it has since helped reduce heat-related deaths through early warnings, public awareness, and response strategies.
- However, most heat action plans remain on paper due to lack of enforcement, poor funding, and limited public awareness.
- Urban Planning and Infrastructure Reforms
- The India Cooling Action Plan (ICAP) aims to improve cooling technologies while reducing energy demand and promoting passive cooling solutions in buildings.
- The Bureau of Energy Efficiency (BEE) has introduced the Energy Conservation Building Code (ECBC) for commercial buildings and Eco-Niwas Samhita for residential structures to encourage climate-friendly construction.
- Local governments need to mandate heat-resistant building materials, increase tree cover, and incorporate urban heat island mitigation strategies.
- Protection for Outdoor Workers and Vulnerable Populations
- Shorter work hours and shaded rest areas should be mandatory for outdoor workers, including traffic police, sanitation workers, and construction laborers.
- The government should resume special working hours during peak summer months, as was done during the COVID-19 pandemic.
- Emergency cooling centers and hydration stations should be set up in urban areas, particularly for those in low-income neighborhoods.
- Early Warning Systems and Public Awareness
- The IMD provides daily heatwave alerts, but many people, especially in rural areas, remain unaware of the risks.
- Community awareness campaigns on heatwave safety, hydration, and first aid for heatstroke should be expanded.
- Mobile-based weather updates and SMS alerts can help citizens take preventive measures in advance.
The Way Forward: Long-Term Strategies to Combat Heatwaves
Addressing heatwaves in India requires a multi-pronged approach involving scientific research, better infrastructure, policy interventions, and public cooperation.
- Strengthening Data Collection and Research
- The IMD should expand its network of weather monitoring stations to provide more localized heatwave forecasts.
- City-specific studies on heat vulnerability should be conducted to identify high-risk zones and develop targeted interventions.
- Universities and research institutions should collaborate on innovative cooling technologies and climate adaptation strategies.
- Water Conservation and Management
- Efficient water management policies are needed to ensure sustainable use of groundwater for agriculture, drinking, and cooling purposes.
- Urban planning should prioritize rainwater harvesting, wastewater recycling, and desalination projects to prevent water shortages during extreme heat events.
- The government must promote heat-resilient crop varieties and agroforestry practices to help farmers cope with rising temperatures.
- Stronger Climate Policies and International Cooperation
- India must accelerate its transition to renewable energy and reduce reliance on fossil fuels, which contribute to global warming.
- The National Green Tribunal (NGT) has called for stricter urban planning guidelines to reduce the urban heat island effect, but enforcement needs improvement.
- Global cooperation is essential in tackling climate change, and India must push for stronger commitments under international agreements like the Paris Accord.
- Recognizing Heatwaves as a National Disaster
- The Karnataka government has requested the Centre to recognize heatwaves as a disaster eligible for National Disaster Response Fund (NDRF) assistance.
- If approved, this could help mobilize more resources for heatwave preparedness and response, particularly for vulnerable communities.
- Local governments must be empowered with decision-making authority and resources to address heat-related emergencies effectively.
Conclusion
Heatwaves in India are no longer isolated climate events but an urgent public health and economic crisis. Rising global temperatures, climate change, and poor urban planning are exacerbating the problem. While policies and heat action plans exist, their implementation remains weak. To protect lives, livelihoods, and the economy, India must take urgent and long-term measures to mitigate the impact of extreme heat. This includes better heat forecasting, improved infrastructure, sustainable urban planning, and stronger worker protection laws. Only through coordinated efforts can India build resilience against the growing threat of heatwaves.
Practice Question
How does climate change contribute to the increasing frequency and intensity of heatwaves in India? (250 words)
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