Observations from a survey
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Key takeaways
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Extreme heat is emerging as a serious problem in Pune. Over the past decade, the number of days when temperature and humidity exceeded safe thresholds has steadily increased. Nights are also becoming hotter and more humid. In addition, longer stretches of consecutive hot days and hot nights are becoming more frequent. This problem is expected to worsen with rising temperatures, rapid expansion of built-up areas and the consequent decline in the city's green cover. Extreme heat can adversely affect human health in multiple ways, ranging from dehydration and heat exhaustion to multi-organ failure and fatal heat stroke.
Low-income households are more at risk from the extreme heat. They often live in poorly ventilated homes that get very hot, have limited means to purchase and operate cooling appliances. It is critical to understand how these households perceive heat risk. If they do not recognise heat as a serious threat, they are less likely to take any protective actions. It is also important to understand their lived experiences such as indoor temperatures, symptoms experienced, health experiences, coping mechanisms, which can provide valuable insights for designing effective heat adaptation interventions.
In this article, we present observations from a survey of 500 low-income households conducted in Pune. The survey covered three housing types: independent houses within slums, old multi-storied buildings in low-income settlements, and multi-storied buildings constructed under the Slum Rehabilitation Authority (SRA). The survey was carried out between 23 April and 6 May 2025. During this period, daytime maximum temperatures recorded by IMD’s automated weather stations ranged from 35°C to 41°C, with average relative humidity levels about 28%. Night-time maximum temperatures ranged from 27°C to 32°C, while relative humidity levels averaged above 50%.
Figure 1 - Map of surveyed localities along with photos of types of houses
Indoor conditions
We used temperature and humidity sensors to record indoor conditions in 48 households over a three-day period. The data show that indoor temperatures in homes with metal roofs rise rapidly during the daytime and are 3–4°C higher than temperatures recorded by the nearest weather station. Although indoor temperatures decrease in the evening, they remain consistently higher than outdoor temperatures throughout the day.
Figure 2 - Average Indoor temperature and humidity values in homes with RCC roofs and Metal roofs
In homes with RCC roofs, indoor temperatures remain relatively stable over the day but peak at around 6 pm. During the daytime, indoor temperatures in these households are lower than those recorded by the nearest weather station, while at night they are higher, indicating heat retention within the building envelope.
Heat wave advisories are typically issued based on outdoor temperature thresholds. However, our findings suggest that indoor temperatures, especially in metal-roofed homes, can be significantly higher, exposing residents to health risks even when outdoor temperatures are lower. Additionally, night-time indoor humidity levels of 40–50%, combined with elevated temperatures, make indoor conditions particularly uncomfortable and increase heat-related stress.
Risk Perception
About 55% of respondents were either unsure or unaware that extreme heat can cause death. This is a serious concern, as a lack of awareness may prevent households from taking protective actions during extreme heat events.
The health impacts of extreme heat vary across individuals, with certain groups being more vulnerable. These include children under five, pregnant women, adults with hypertension or diabetes, and senior citizens. In the surveyed households, approximately 23% of total household members fell into one or more of these vulnerable categories. Of particular concern is the high prevalence of hypertension and diabetes. Among adults above 35 years of age, information about hypertension was available only for 81% of the people. 78% of them are reported to be tested for hypertension, and 30% of those tested, were reported to have hypertension. In case of diabetes information of 60% adults above the age 35 was available. 56% of them were reported to be tested for diabetes, and 21% of those tested, were reported to have diabetes.
Around 8% of respondents reported knowing someone who had become seriously ill or died due to extreme heat. This is notable given that heat-related illnesses and deaths are often difficult to identify and formally attribute to heat exposure.
Discomfort and impact on health
Respondents were asked to describe their experience during the summer, ranging from minor discomfort to very high levels of discomfort. More than half (56%) of all respondents reported experiencing very high discomfort in their homes during summer. This proportion rises to 72% among households with metal roofs. These perceptions are supported by indoor measurements, which show that temperature and humidity levels inside these homes are consistently higher than outdoor conditions.
Respondents were asked whether any household members had experienced specific health issues due to heat (see Figure 3). Every surveyed household reported at least one symptom of heat-related illness (HRI), and 75% of households reported more than three symptoms. Excessive sweating, dehydration, body ache, headache, and dizziness were the most commonly reported symptoms.
When initially asked in general terms, respondents mentioned only a few symptoms spontaneously. However, when later probed about specific symptoms, a much larger proportion of households reported experiencing them. This indicates that while people do experience symptoms of heat-related illness, they do not always recognise or attribute these symptoms to heat exposure.
Figure 3 - Reported Heat Related Illness (HRI) symptoms
About 43% of respondents sought medical help for heat-related symptoms. 62% usually visited private facilities for medical treatments. Anecdotal evidence suggests this is mainly due to a mismatch between public facility hours and people’s working hours. Around 76% of respondents reported having no health insurance for themselves or their families. This may result in a significant financial burden if heat exacerbates an existing medical condition and leads to hospitalization.
Figure 4 - Patterns of seeking medical help
Coping with heat
Reliable electricity and water supply are critical for coping with extreme heat. Almost all surveyed households reported receiving adequate water supply. However, since the survey did not capture the number of hours of water supply, the term adequate may reflect relatively low expectations of service levels. Nonetheless, none of the households reported purchasing drinking water.
Similarly, majority of respondents reported no or only minor interruptions in electricity supply. This perception may also be influenced by lower expectations regarding the quality and reliability of electricity services from the local distribution company.
Only 1% of households reported having white-painted roofs. White roofs can reduce indoor temperatures by 2–3°C according to studies in Nagpur, Hyderabad, and Delhi. About 90% of those without white roofs were unaware of these benefits, indicating a major awareness gap. However, even with awareness, willingness to pay may remain low due to limited perceived health risks, which needs to be examined further.
Almost all households own ceiling fans, and about 30% own table fans. About 25% own evaporative coolers, while 60% own refrigerators. Fans show no clear effect on reported heat discomfort. Coolers reduce discomfort during the day, as fewer households with coolers report discomfort than those without. At night, coolers are less effective due to small, poorly ventilated rooms and high humidity. Refrigerators also reduce discomfort during the day, likely by providing cold water. Neither coolers nor refrigerators show a noticeable effect at night. In small rooms, refrigerators can be a significant source of heat, as their cooling cycle releases heat into the room. 
Figure 5 - Ownership of appliances and impact on discomfort
We also asked households to report their electricity bills. The median bill increased by about 10% in March compared to January, reflecting the early onset of summer in 2025. Bills for April and May, may be even higher. Based on reported appliance ownership, monthly consumption during summer should be around 100 units, which should result in a bill of about ₹650. However, households reported a median bill of ₹1000, with values ranging from ₹400 to ₹3,000. This gap needs further examination. Almost all households reported having independent electricity meters. This rules out average billing, where the distribution company charges households based on standard norms without a meter, and sub-metering, where multiple households share one meter and the total bill is divided among them. One likely explanation is the use of inefficient appliances, which can significantly increase electricity costs. This needs to be examined further.
Figure 6 - Reported electricity bills
Summary
Satellite data, weather station data, and our indoor measurements show that temperature and humidity inside low-income homes in Pune often exceed levels at which heat can seriously affect health. Indoor conditions are consistently worse than temperatures recorded by weather stations, which are used for public health advisories.
Some awareness of heat exists, but quite a few households do not believe it can cause serious illness or death. Many report symptoms of heat-related illness but do not link them to heat exposure. The majority sought treatment at private clinics and lacked health insurance coverage. This highlights their vulnerability to financial distress in the event of a serious heat-related illness.
Most households report adequate water and electricity supply. Ceiling and table fans are widely used but do not appear to reduce reported discomfort. Coolers and refrigerators provide some relief during the daytime. However, high electricity bills are a concern. Very few have white-painted roofs, and awareness of their benefits is low. However, even with awareness, willingness to pay may remain low due to limited perceived health risks.
Overall, the survey indicates that low-income households are already experiencing significant health impacts, although they may not attribute these effects to extreme heat. The findings highlight the need for better communication on heat-related health risks, affordable healthcare access, and effective, low-cost heat adaptation measures, along with an assessment of their impact on household expenses.
Suggested citation: Prayas (2026, March), ‘Extreme heat and low Income households in Pune city’
An article based on this article appeared in The Indian Express as Trapped heat forces low-income Pune households into ‘quiet suffering, exhaustion’: Study on 22 April 2026
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The authors thank their colleague Ritu Parchure for reviewing the article. They also wish to thank Rashmi Rohan for conducting the surveys.
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