India is heading into a scorching summer as the Indian Meteorological Department (IMD) predicts above-normal temperatures from April to June. The country has already witnessed an unusually warm start to the year, with January, February, and March recording higher-than-usual temperatures. As the summer months progress, the IMD has warned that several states will experience more frequent and intense heatwaves.

With climate patterns shifting and extreme weather events becoming more common, understanding the causes of heatwaves and their impact is crucial. In this article, we explore what heatwaves are, how they occur, and the challenges they pose.

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What is a Heatwave?

A heatwave is a prolonged period of excessively high temperatures, typically occurring in India between March and June. The IMD defines a heatwave based on regional temperature thresholds:

• Plains: 40°C or above

• Hilly regions: 30°C or above

• Coastal areas: 37°C or above

When temperatures soar beyond these limits for an extended period, it can have severe consequences for human health, agriculture, and infrastructure.

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Why Do Heatwaves Occur?

Heatwaves are caused by a combination of global and local factors. With rising global temperatures and changing weather patterns, heatwaves are becoming more frequent and intense. Here are the key reasons why they occur:

1. Global Warming and Climate Change

The long-term rise in global temperatures due to greenhouse gas emissions has led to an overall increase in extreme weather events, including heatwaves. Warmer global temperatures mean that heatwaves last longer and occur more frequently.

2. Changing Atmospheric Conditions

• High atmospheric pressure systems in northern India result in clear skies and reduced wind movement, trapping heat near the surface. This lack of cloud cover prevents cooling through rainfall.

• Delayed western disturbances, which usually bring rain to northern India, can extend heatwaves as cooling showers arrive later than expected.

3. Urban Heat Island Effect

Cities experience higher temperatures than rural areas due to increased concrete structures, reduced greenery, and high population density. Urbanization and deforestation contribute to ‘urban heat islands’, where heat gets trapped, making cities significantly warmer than surrounding regions.

4. Hot, Dry Winds (Loo Effect)

In western India, especially in the Thar Desert region, Loo winds—hot and dry air currents—further intensify heatwave conditions. These winds, combined with rising temperatures, make northern and central India particularly vulnerable to extreme heat.

5. Early Onset of Heatwaves

India witnessed its first-ever winter heatwave in February 2024, with unseasonably high temperatures in Goa and Maharashtra. Experts suggest that if current trends continue, cities like Bengaluru could become hotter than Delhi by 2030.

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Why Are Heatwaves a Major Concern?

Heatwaves are not just about discomfort; they have far-reaching consequences:

Health Hazards: Prolonged exposure to extreme heat can lead to dehydration, heatstroke, and even fatalities. Vulnerable populations, such as the elderly, children, and outdoor workers, face the highest risks.

Impact on Agriculture: Crops such as wheat and pulses are sensitive to extreme heat, and prolonged heatwaves can reduce yields, leading to food shortages and price hikes.

Power and Water Crisis: Increased demand for electricity due to air conditioning and cooling appliances can strain the power grid, leading to outages. Water scarcity worsens as rivers and reservoirs dry up.

Economic Challenges: A significant portion of India’s workforce is engaged in outdoor labor (such as construction, farming, and street vending). Extreme heat can reduce productivity, impact livelihoods, and cause economic losses.

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Are Heatwaves Considered a Disaster in India?

Despite causing hundreds of deaths every year, heatwaves are not classified as a “notified disaster” under India’s Disaster Management Act, 2005. For an event to be officially recognized as a disaster, it must be deemed beyond the coping capacity of affected communities.

Experts argue that heatwaves should be included in disaster planning, as their impact is becoming more severe due to climate change. Recognizing them as a disaster would allow for better preparedness, resource allocation, and relief efforts.

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How to Stay Safe During a Heatwave?

With heatwaves expected to intensify in the coming months, it is essential to take precautionary measures to stay safe:

Stay Hydrated: Drink plenty of water throughout the day to prevent dehydration. Avoid caffeine and alcohol, as they can lead to further dehydration.

Avoid Direct Sunlight: Stay indoors during peak afternoon hours (12 PM – 4 PM) when temperatures are highest. If you must go outside, wear loose, light-colored clothing and use sunscreen.

Use Cooling Measures: Keep your home cool by using fans, air conditioners, or coolers. Placing wet towels on your body or taking cold showers can help regulate body temperature.

Eat Light and Nutritious Meals: Opt for water-rich foods like fruits and vegetables. Avoid heavy, spicy, or fried foods that generate body heat.

Check on Vulnerable Individuals: The elderly, children, and individuals with pre-existing health conditions are at higher risk. Ensure they have access to cooling methods and stay hydrated.

Recognize Signs of Heatstroke: Symptoms include high body temperature, dizziness, confusion, and rapid heartbeat. Seek immediate medical help if you or someone around you shows these symptoms.

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Looking Ahead: Addressing Heatwave Challenges

As heatwaves become more frequent due to climate change, India must adopt proactive measures:

Increasing Green Cover: Planting more trees and creating urban green spaces can help reduce the impact of the urban heat island effect.

Improving Building Designs: Promoting heat-resistant construction materials and ventilation-friendly architecture can help keep homes cooler.

Enhancing Water Conservation: Strengthening water conservation methods, such as rainwater harvesting, will be crucial in addressing water shortages during extreme heat.

Public Awareness Campaigns: Educating people about heatwave risks and safety measures can reduce fatalities and health emergencies.

Government Action: Recognizing heatwaves as a disaster and developing heat action plans for high-risk regions can ensure better preparedness and response.

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Final Thoughts

With global temperatures rising, heatwaves in India are expected to become more severe in the coming years. While extreme heat is an annual occurrence, its increasing intensity poses a serious threat to health, agriculture, and the economy. By taking preventive measures and advocating for stronger policies, India can minimize the impact of heatwaves and protect vulnerable populations.

As we move into the hottest months of the year, staying informed and prepared will be key to tackling the challenges of extreme heat. Stay safe, stay hydrated, and take necessary precautions to beat the heat!