There were at least 46 deaths reported in May 2024 and 56 in March due to heat strokes in India. As reported in this newspaper, the weeks between May 15 and May 28 saw many parts of the country averaging temperatures a whopping three degrees Celsius higher than average. While these extreme outcomes catch our attention, the reality is that prolonged periods of extreme heat — what we are witnessing in many parts of India — pose more generalised health risks. Those who cannot adequately shelter themselves in cool places and drink enough water are prone to insomnia, fatigue, headache, fever, and more severe illnesses.
Beyond quality of life issues, when people are unable to deal with extreme heat, economic productivity and livelihoods suffer. In a country where a significant share of the workforce is engaged in heat-exposed work, the productivity of the manufacturing and agricultural sectors is at stake. Experts predict that the manufacturing sector alone will bear a loss of 15% this May. To date, there is little structured thinking on how we can cope with extreme heat and almost no data on the prevalence of illness during periods of extreme heat.
In order to address this gap, and assess the health impacts of extreme heat, the Centre for Rapid Insight (CRI) conducted a rapid poll on May 28-30 of 12,496 people across 20 states and Union territories, covering 421 of India’s 543 parliamentary constituencies. We asked the following question, “In the past month, have you or anyone in your household experienced illness, such fever, vomiting, headache, or dizziness, due to the heat outside?”
The rapid poll was conducted on mobile phones using Interactive Voice Response (IVR) technology, followed by a rigorous process of estimation and weighting using the National Family Health Survey (NFHS) as an anchor to provide representative claims of those households that own a mobile phone. The rapid poll confers significant advantages to brick-and-mortar standard surveys — a survey of this size and scale could take months to run with huge financial costs and the inability to target the hottest weeks of the year, as we have done here.
In our data, we found a staggering 45% of households reporting at least one member falling ill due to the heat in the past month. Of those who reported a household member falling ill due to the heat, more than 67% reported household members falling ill for more than 5 days in the past month. Naturally, this is most felt among the lowest socioeconomic strata in society. A total of 32.5% of households with a two-wheeler, and a total of 28.2% of households with no motorised vehicle reported having a household member who experienced illness for more than five days; this number dropped to 21.8% among households with cars.
This is not just a question of economic wealth – those who do not own cars are prone to significantly more heat exposure in their daily movements. This is also likely an underestimate on the impact of heat on the poorest in society, as our survey results are representative of households that own a mobile phone.
Heat stress also has a varied impact, based on gender, socio-economic status, location and the type of work. Women may be more susceptible to heat-induced illnesses as they work longer in the kitchen (often, by chulhas). This makes them vulnerable to heat stress even at home, which is particularly risky or harmful for pregnant and menstruating women. Similarly, communities in dense, low-income, urbanised neighbourhoods with significant built-up area and little green cover are especially vulnerable. Bearing the disproportionate impact of urbanisation and rising temperatures, these neighbourhoods lack heat-conducive infrastructure and tend to retain the heat accumulated during the day. An effective heat mitigation strategy requires recognising the differential impacts of heat, and crafting strategies to address the needs of the most vulnerable populations.
While more states are starting to adopt Heat Action Plans (HAPs), there are concerns regarding the extent to which these are being implemented. For instance, only two of 37 HAPs currently in place in India conduct vulnerability assessments to identify and target affected communities. Furthermore, HAPs include the need to develop and institutionalise monitoring systems to ensure compliance. As the climate crisis and excessive built area start to produce more episodes of extreme heat, it is also important that we invest in long term strategies such as cooling shelters and increased green cover.
(This is the first instalment in a new series that uses insights from rapid polling across the country on topical issues. The polls are run by the Centre for Rapid Insights (CRI), based at Artha Global. Neelanjan Sircar is its director.
The polls have a sample of about 13,000 to 15,000 households across India covering 421 of 543 Lok Sabha constituencies. NFHS data is then used to re-weight the data to be representative of households with mobile phones down to the assembly constituency level. The estimations themselves are done using the technique of multilevel modelling, which helps account for different caste, wealth, and spatial demographics in the measurement.)
