As Delhi on Sunday recorded its highest minimum temperature in April in three years with the mercury settling at 26 degrees Celsius, 4.4 degrees above the season’s average, the Delhi government is likely to announce a heat wave action plan on Monday.
The last time the city saw such high minimum temperature was in 2022, when it touched 26.2 degrees Celsius. The maximum temperature on Sunday was at 39.8 degrees Celsius, three notches above normal. Humidity levels fluctuated between 63 per cent and 38 per cent.
The plan proposed that different departments should ensure availability of shade, drinking water, ORS packets etc., at bus and auto stands, proper shade for traffic police, using non-functional schools as shelters and altering the timing of outdoor workers to minimise exposure to intense heat. According to the plan, health facilities must maintain a database of patients coming in with heat-related illnesses in the emergency and the associated mortality for surveillance.
This Heat Action Plan aims to provide a framework for the implementation, coordination, and evaluation of extreme heat response activities in Delhi that reduce the negative health impacts of extreme heat.
The Plan’s primary objective is to alert those populations most at risk of heat-related illness that extreme heat conditions either exist or are imminent, and to take appropriate precautions.
The draft of the action plan stated that there will be no harm to the human body if the environmental temperature remains at 37° C. Whenever the environmental temperature increases above 37° C, the human body starts gaining heat from the atmosphere. If humidity is high, a person can suffer from heat wave disorders even with the temperature at 37°C or 38°C. To calculate the effect of humidity we can use Heat Index Values. The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.
According to the India Meteorological Department (IMD), the minimum temperature in Palam recorded 24.7 degree Celsius; Lodhi Road 25.4 degree Celsius; Ridge 25.3 degree Celsius and Ayanagar 25.6 degree Celsius. A similar trend was observed in 2022, when the highest minimum temperature in April was recorded at 26.2 degrees Celsius.
A ‘warm night’, as defined by the IMD, occurs when the minimum temperature departs from normal by 4.5 degree celsius to 6.4 degree celsius, and is only declared if the maximum temperature remains at 40 degrees Celsius or more. In 2024 and 2023, the minimum temperature did not touch 25 degrees Celsius in April, according to the weather department. The highest minimum temperature in 2024 was 24 degrees Celsius, while in 2023, it was 23.6 degrees.
According to the weather office, a heatwave is declared when the maximum temperature in the plains reaches at least 40 degrees Celsius or when the temperature departs from normal by 4.5 to 6.4 degrees Celsius.
The weather department has forecast a partly cloudy sky for Monday, with the maximum and minimum temperatures hovering around 40 and 25 degrees Celsius, respectively.
Meanwhile, the city’s air quality was in the ‘moderate’ category at 4 pm on Sunday, with the Air Quality Index (AQI) recorded at 140, according to the Central Pollution Control Board. An AQI between zero and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, and 401 and 500 severe.