On Wednesday, April at 2.30pm, the temperature in the National Capital Region (NCR) reached a scorching 52.3 degrees Celsius, making it the hottest day ever recorded in the region, according to a screenshot taken by Mint. Earth sciences minister Kiren Rijuju later stated that this was “not official yet” and described such a high temperature as “very unlikely,” requesting the weather office to verify the report.
Nonetheless, India has been experiencing extremely hot weather conditions, both in terms of duration and intensity. Most of April and May have been marked by heatwave or “severe heatwave” conditions, particularly in regions of Central, North, and Peninsular India. States like Rajasthan, Punjab, Haryana, Delhi, Uttar Pradesh, Chhattisgarh, Odisha, Karnataka, Andhra Pradesh, Telangana, and Tamil Nadu have been among the worst affected, while non-heatwave zones like Kerala and Sikkim have also begun to experience it.
Various studies indicate a significant rise in humidity levels and a reduced rate of night-time cooling, both of which have contributed to the increased intensity of the heatwave. These changes have been attributed to two primary factors: El Niño, a weather pattern that causes abnormal warming of waters in the equatorial Pacific Ocean, which often leads to heatwaves and extreme heat conditions worldwide, and the presence of high-pressure systems over the Southern peninsula and South-Eastern coastal areas. These systems push warm air closer to the Earth’s surface, contributing to the heat, and hinder the flow of sea breeze that would otherwise cool the land, resulting in reduced night-time cooling.
The definition of a heatwave, as per the weather office, is when temperatures exceed 40°C or are 4.5°C above normal in the plains, while in coastal regions it is 37°C or 4.5°C above normal. For a heatwave to be declared, at least two weather stations within a sub-division must record these temperatures for two consecutive days. In the case of a severe heatwave, the temperature must be 6°C above normal.
In recent years, the duration and severity of heatwaves have increased significantly. Previously lasting four to eight days, heatwaves now persist for as long as 20 days. Within the past two years alone, India has experienced an unprecedented 328 heatwave days, making 2023 the hottest year on record. Experts attribute this trend to climate change, which is known to exacerbate the intensity and frequency of extreme weather events.
The extreme heat has taken a toll on the population, with anecdotal evidence suggesting an increase in heat-related deaths. However, due to the absence of nationwide data on heatwave deaths, policy response has been slow.
To address the challenges posed by heatwaves, India developed its first heatwave action plan three years after a heatwave claimed 800 lives in Ahmedabad in May 2010. The plan involves the establishment of an early warning system, improvements to the healthcare system, and awareness campaigns. While many states have implemented similar action plans, experts emphasize the need for redefining the criteria for heatwave declarations, incorporating humidity levels, customizing plans to local conditions, and making information available at the district level. Access to localized heatwave intensity data will enable officials to take more effective pre-emptive measures.
