Over 75% Indians At ‘High’ To ‘Very High’ Heat Risk: CEEW Study
The study shows North India’s summer humidity has climbed from 30-40 per cent to 40-50 per cent in the last decade, worsening heat stress for outdoor workers
A recent study by the Delhi-based think-tank Council on Energy, Environment and Water (CEEW) reveals alarming statistics about heat risk in India. According to the report published on May 20, approximately 57 percent of Indian districts, which are home to 76 percent of the country’s total population, are currently classified as being at ‘high’ to ‘very high’ heat risk.
The study identifies the ten states and union territories with the highest heat risk: Delhi, Maharashtra, Goa, Kerala, Gujarat, Rajasthan, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, and Uttar Pradesh. “Our study found that 417 out of 734 Indian districts fell in the high and very high risk categories,” stated Vishwas Chitale, senior programme lead at CEEW. This includes 151 districts under high risk and 266 under very high risk. In contrast, 201 districts were categorized as moderate, while 116 fell into low or very low categories. Chitale emphasized, “This does not mean that these districts are free of heat risk, but that it is relatively lesser than that of other districts.”
The study highlights a concerning trend: the number of very warm nights is increasing at a faster rate than that of very hot days over the past decade. Very warm nights and very hot days are defined as periods when minimum and maximum temperatures exceed the 95th percentile threshold, which reflects what was considered normal for 95 percent of the time in the past. The researchers developed a Heat Risk Index (HRI) for 734 districts, utilizing 40 years of climate data (1982–2022) and satellite imagery to analyze heat trends, land use, water bodies, and green cover.
The findings indicate that high night temperatures pose significant health risks, as the body does not have the opportunity to cool down. This phenomenon is exacerbated in urban areas due to the urban heat island effect, where metropolitan regions are significantly hotter than their rural surroundings. “The rise in very warm nights is most noticeable in districts with a large population (over 10 lakh), which are often home to Tier-I and Tier-II cities,” the report noted. For instance, Mumbai experienced an increase of 15 very warm nights per summer, while Bengaluru saw 11 additional nights.
Even traditionally cooler regions, such as the Himalayan areas, are not immune to these changes. The study revealed that in Jammu and Kashmir and Ladakh, the number of very hot days and very warm nights has risen by over 15 days and nights each summer. This shift poses a severe threat to fragile mountain ecosystems.
The report also highlights the increase in summer humidity in north India, which has climbed from 30-40 percent to 40-50 percent over the last decade. This rise in humidity worsens heat stress, particularly in the Indo-Gangetic plain, where outdoor workers are significantly affected. “Early mornings now feel hotter due to humid conditions,” the researchers noted, with cities like Delhi and Jaipur experiencing a 6–9 percent rise in perceived temperature.
CEEW researchers pointed out that cities like Mumbai and Delhi, along with much of the Indo-Gangetic plain, face the highest exposure to heat risks due to high population density and existing socio-economic challenges. In contrast, districts in Odisha, which have more green cover and water bodies, are better equipped to cope with rising temperatures.
The study warns that extreme heat is becoming increasingly common, with 2024 already recorded as the hottest year in India and globally. “Severe and frequent heatwaves are further burdening low-income households,” the report states, highlighting the challenges faced by outdoor workers who must take frequent breaks to cope with the heat. Experts predict that India could lose the equivalent of 35 million full-time jobs and experience a 4.5 percent reduction in GDP by 2030 due to these rising temperatures.
The World Health Organization reports that over 166,000 people died from heatwaves between 1998 and 2017, and last year, India logged over 48,000 heatstroke cases and 159 heat-related deaths. Experts caution that India may be undercounting heat-related fatalities, underscoring the urgent need for action to address this escalating crisis.
