What is Heat Wave and Heat Stroke?

1. What is a Heat Wave?
A heatwave is a natural weather phenomenon that occurs when the temperature in a region rises significantly above normal levels. According to the Indian Meteorological Department (IMD), if the temperature in plains reaches 40°C or more for at least two consecutive days, it is classified as a heatwave. For coastal areas, the threshold is 37°C, and for hilly regions, it is 30°C. A fluctuation of ±4.5°C is considered within the heatwave range. Heatwaves affect the elderly, children, and the ill most severely and pose a serious public health risk, especially during prolonged hot spells.

2. How Does Heat Stroke Occur?
Heat stroke is a life-threatening medical emergency that happens when the body’s internal temperature rises above 40°C and can no longer cool itself naturally. It often results from prolonged exposure to high heat, excessive sweating, and insufficient water intake. The body’s temperature regulation system fails, leading to potential damage to the brain, kidneys, and other vital organs. Symptoms include intense headache, dizziness, vomiting, rapid heartbeat, and unconsciousness. Without immediate treatment, heat stroke can be fatal. It is critical to act quickly by cooling the person and seeking medical help to prevent serious complications.

3. Why Are Heatwaves Increasing in India and How Is It Linked to Climate Change?
In a tropical country like India, heatwaves are intensifying and becoming more frequent due to climate change. Rising global temperatures are increasing the average surface temperature, causing longer and more severe heatwave events. Factors like urbanization, deforestation, and the loss of natural heat barriers also contribute. According to IMD and climate reports, heatwave incidents in India have shown a rising trend each decade. In 2022, temperatures in Delhi and Rajasthan touched 49°C. Climate change is no longer just a global concern—it poses a direct threat to public health, agriculture, and overall environmental stability in India.