Extreme heat poses great risks in India

A new independent study by the Council on Energy, Environment and Water (CEEW) in India warns that Extreme heat now poses a risk to 57 per cent of Indian districts – home to 76 per cent of the population. The CEEW’s study, ‘How Extreme Heat is Impacting India: Assessing District-level Heat Risk’, presents a first-of-its-kind composite heat risk assessment of 734 districts in India using 35 indicators, offering a granular picture of how climate change has reshaped heat hazard trends from 1982 to 2022.

The CEEW analysis points out that in 2024, India experienced its longest recorded heatwave since 2010. At this juncture, India must rapidly scale up its heat resilience. To achieve this, a granular, data-driven understanding of the heat risk faced by every district in the country is one of the first and most crucial step.

With Indian cities and districts increasingly navigating complex and erratic climate patterns, the need for heat-resilient planning and governance becomes urgent, says a CEEW press release on the study. Adding that the India Meteorological Department has recently issued heatwave alerts in Uttar Pradesh and Rajasthan, even as parts of South and Northeast India saw rain warnings, the press release states that the study finds that the top 10 most heat-risk-prone states and union territories (UTs) are Delhi, Andhra Pradesh, Goa, Kerala, Maharashtra, Gujarat, Rajasthan, Karnataka, Tamil Nadu, and Uttar Pradesh.

Of the 734 districts, 417 districts fell in the high and very high risk categories while 201 were classified as moderate risk. The remaining 116 low-risk districts are not immune, only relatively less exposed. The CEEW study highlights three key trends: an alarming rise in very warm nights; increasing relative humidity across North India, particularly in the Indo-Gangetic Plain; and heightened heat exposure in dense, urban, and economically critical districts such as Delhi, Mumbai, Ahmedabad, Hyderabad, Bhopal, and Bhubaneswar. Further, some rural districts in Maharashtra, Kerala, Uttar Pradesh, and Bihar – home to large numbers of agricultural outdoor workers – were also found to fall in the high to very high heat risk category.

According to the CEEW study, approximately 70 per cent of districts have seen more than five additional very warm nights per summer over the past decade (2012-2022) compared to the climatic baseline (1982-2011). Very warm nights are defined as nights when the temperature stays unusually high – warmer than what used to be normal 95 per cent of the time in the past. By contrast, only approximately 28 per cent of districts saw a similar increase on very hot days. These warmer nights are rising faster than hot days and make it harder for the human body to cool down and recover from daytime heat. In the last decade, residents in Mumbai experienced 15 more very warm nights each summer compared to the previous three decades, while Jaipur and Chennai saw increases of seven and four nights, respectively. Urban heat islands that trap heat during the day and release it at night are likely driving this trend. This has serious health implications, especially for the elderly, outdoor workers, children, and people with pre-existing conditions such as hypertension and diabetes, in both urban and rural areas.

The key recommendations of the study include going beyond just daytime temperatures when planning for heat risk reduction; tapping into State Disaster Mitigation Funds (SDMFs); asking states where more than half of districts face high heat risk to notify heatwaves as a state-specific disaster; promoting heat insurance to protect livelihoods; and creating a national repository of heat action plans (HAPs). It also recommends that HAPs be regularly updated using granular data and expanded to include measures for night-time heat and humidity stress. These findings, says the media release, come at a critical time, as states now have access to the SDMFs, which in 2024 included heatwaves as an eligible disaster category. This enables state governments to mobilise dedicated funding for proactive and long-term heat resilience planning based on risk profiles. The CEEW is currently supporting the development and strengthening of over 50 localised city and district-level HAPs across six states in India. Through ward-level heat risk assessments, the goal is to enable more than 300 such plans by 2027.