IMD issues red alert for heatwave across Delhi, Punjab, Haryana and Rajasthan

The India Meteorological Department (IMD) has issued a red alert for heatwave conditions across Delhi, Punjab, Haryana, and most parts of Western Rajasthan, effective Sunday. The agency has warned that heatwave and severe heatwave conditions are likely to prevail in these regions for five consecutive days starting Sunday. Cities including Delhi and Chandigarh have recently recorded temperatures around and above 44°C.

A heatwave is defined by the IMD as a condition where air temperature becomes potentially fatal to the human body upon exposure. Quantitatively, a heatwave is declared when the maximum temperature reaches at least 40°C in plains, 30°C in hilly regions, or when coastal areas record a departure of 37°C or more from normal. These conditions must be observed at a minimum of two stations in a meteorological sub-division for at least two consecutive days, with the declaration made on the second day.

A heatwave is classified when temperatures exceed normal by 4.5°C to 6.4°C. A rise of more than 6.4°C is categorised as a severe heatwave. May is typically the peak month for heatwaves in India, affecting regions such as Punjab, Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand, West Bengal, Odisha, Madhya Pradesh, Rajasthan, Gujarat, parts of Maharashtra and Karnataka, Andhra Pradesh, and Telangana. Maximum temperatures above 45°C are commonly observed in Rajasthan and the Vidarbha region during this month.

The red alert signifies an extreme heat warning, issued when a severe heatwave persists for more than two days or when the total number of heat or severe heatwave days exceeds six. According to the IMD, there is a very high likelihood of heat illness and heat stroke across all age groups under such conditions. Vulnerable populations, including the elderly, infants, and those with chronic diseases, require extreme care. In response, the Chandigarh administration is reportedly considering closing schools by noon.

Climate scientists have noted that human-caused climate change has made such intense heat events significantly more likely. The World Health Organization has reported that more than 1,66,000 people died due to heatwaves globally between 1998 and 2017.

The National Disaster Management Authority (NDMA) recommends several precautions to minimise heatwave impact. These include avoiding sun exposure between noon and 3 pm, wearing lightweight and light-coloured cotton clothing, using hats or umbrellas when outdoors, and drinking water frequently even without feeling thirsty. Alcohol, tea, coffee, and carbonated drinks should be avoided as they dehydrate the body. Instead, oral rehydration solutions and homemade drinks like lassi, rice water, lemon water, and buttermilk are advised.

In case of heatstroke, the affected person should be moved to a cool, shaded place and their body wiped with a wet cloth. Pouring normal-temperature water on the head can help bring down body temperature. The person should be given ORS or hydrating liquids and taken to the nearest health centre immediately, as heat strokes can be fatal.