Extreme heat imperils chronic disease patients in informal settlements

Within hours of sunrise, the two-room flats in the government-constructed apartment in New Rajarajeshwari Peta in Vijayawada feels like a pot on a stove.

By 11 am, Vidya (name changed) sits outside her home with her neighbours under the shade of a tree. The women chat and laugh, relieved to escape the summer heat inside the house. Vidya who is in her late 30s lives on the ground floor or a four-storey building, in a resettlement colony constructed more than a decade ago for low income families.

“Ee vadagaalpula valla intlo baaga aaviri vachesthundi. With these hot winds, heat builds up in the house like steam. I find it difficult to breathe sometimes,” she said.

But for Vidya, it is more than just physical discomfort. She is diabetic and feels her condition worsen during the summer. Extreme heat is known to exacerbate health risks of those living with chronic diseases.

About 57 percent of Indian districts, home to 76 percent of the country’s population, are at high to very high heat risk, a 2025 study by Council on Energy, Environment and Water (CEEW) showed. Andhra Pradesh is among the most heat-prone states.

A study done by the India Meteorological Department’s scientists published this year shows that the average maximum temperature across India increased by ~0.5°C by 2000, and by ~1.0°C by 2020. Northwestern and central India and the coast of Andhra Pradesh experienced the most significant increase. Between 1981 and 2000, these regions experienced an average of 2.5 to 5.5 heatwave days per year.

However, over the two decades between 2001-2020, the frequency of heatwaves has increased with 3.5-8.5 days per year, particularly in northern, western, south-central, central-east, and peninsular India.

IMD has forecast heatwave to severe heatwave conditions in 17 states and Union territories, including parts of Andhra Pradesh such as Vijayawada and Guntur.

IndiaSpend reached out to the Union and state health ministries for comment. We will update this story when we receive a response.

How heat affects those with comorbidities

“The body’s homeostatic mechanism, meaning how we adapt to any change in our external environment, such as high heat, becomes impaired in those with chronic diseases like hypertension, diabetes, renal disease, among others,” said Vivekanand Jha, executive director at The George Institute for Global Health, India, and a nephrologist and public health researcher.

For blood pressure patients, excessive sweating can lead to a drop in blood pressure. “We have seen in clinics that people with well-controlled hypertension suddenly experience low blood pressure during extreme heat. They become giddy and weak. And when we measure their blood pressure, it is low. So, during the summer months, we have to reduce the number of blood pressure medicines, especially diuretics, which increase the urine flow, increasing loss of fluid,” Jha added.

Diabetics are at greater risk for heat-related illnesses because of their impaired capacity to dissipate heat, and this can have important consequences on cardiovascular regulation and glycemic control.

For insulin-dependent diabetics, during extreme heat, the body is unable to absorb insulin, resulting in uncontrolled sugar levels. “Insulin needs refrigeration at 4 degrees Celsius. Many in informal settlements don't have access to a fridge, so obviously they don't have access to effective insulin.,” Jha explained.

In renal disease, the loss of salt and water due to excess heat can result in loss of kidney function. “Let's say a manual worker goes out to work in extreme heat from morning to evening,” he continued. “By evening, their kidney function becomes lower than normal. The kidney function may recover after the worker returns home and has water for the day, but repeated insults to the organ can result in long-term injury, resulting in chronic kidney disease which can progress to kidney failure.”

Gig and platform workers without access to toilets avoid drinking water, which ends up impacting their kidneys, as IndiaSpend reported in April 2026.

Extreme weather can also trigger hospital visits and mortality risk as the body struggles to regulate itself under heat stress. For Vidya and other residents of informal settlements, who are already more vulnerable to the effects of climate change, the additional burden of having a chronic health condition poses further risk.

Mounting health problems

A couple years ago, Vidya used to run a food cart cooking and selling breakfast items such as dosa and idli, when she met with an accident. Hot oil spilt on her leg, and refused to heal for a long time. She finally had to go to a private hospital in the city where the doctors had to remove one of her toes. The surgery cost her Rs 1.2 lakh, which she borrowed from an informal lender for 10 percent interest per month. She continues to have a persistent wound.

“Everyday I put on the glove and do the dressing of this wound myself,” she said.

She was first diagnosed with diabetes when she was pregnant with her second child more than a decade ago. She goes to the primary health centre (PHC) near her house every month, where her blood sugar levels are checked and she gets her medicines. The PHC staff with whom around 200 diabetics are registered informed us that the blood sugar levels among the diabetics rises above their usual levels during summer.

“I follow everything the doctor says. I take the medicine and follow the diet. But my sugar levels are often not in control,” she said. Because of her uncontrolled diabetes and the persistent wound on her leg, Vidya had to give up working outside home.

Vidit Panchal, a public health physician who has worked in several parts of rural India, and with poor and tribal populations, said more evidence needs to be generated related to effects of extreme heat among people living in informal settlements.

“There is not much primary evidence from different parts of India on how heat is impacting health outcomes of people in informal settlements,” said Panchal, now based in Udaipur. He added that triaging protocols that are simplified and contextual in dealing with heat stress and heat-related illnesses can help prevent deaths.

Jha said the country’s primary healthcare sector needs to be strengthened towards identifying and treating heat-related illnesses, given these events are only likely to increase.

“Our primary healthcare sector is not sufficiently oriented to identify and manage heat-related illnesses. When people come to the PHC complaining of exhaustion or weakness, doctors often don't recognize it as a heat-related illness. Sometimes they are given painkillers because they have a bodyache, which worsens the injury, as painkillers are harmful to the kidneys. Many PHC records often show no admissions or visits due to heat-related illnesses,” said Jha, who is involved in research projects in Srikakulam district in Andhra Pradesh, and in Chhattisgarh investigating the effect of heat on health.

The Ministry of Health and Family Welfare has in its training module for doctors basic guidelines on how to handle those with chronic health conditions.

These have not reached the primary care doctors yet,” said Jha. “We need to make sure these guidelines reach the population they are intended to reach. We need to do implementation research to help understand that. We need to move beyond making generic recommendations to more specific recommendations, which can help doctors tailor their treatment according to an individual’s needs.

No relief at home

Government public health advisories talk about staying indoors during extreme heat, which is practically impossible for outdoor workers working on daily wage. And in the case of those living in informal settlements, staying home provides little comfort.

Thirty-five-year-old Radha (name changed) lives in Sarada colony, an informal settlement in Guntur. The settlement is lined with semi pucca houses to makeshift houses with corrugated iron roofs. Most of them barely have any ventilation, and heat up immensely during the summer, when temperatures hit upwards of 40°C.

Radha is a widow and has had a physical disability since she had surgery for severe back pain four years ago, after which she could not move her legs any longer due to a spinal injury. She used to work as a waste picker and hair collector (workers go house to house asking for women to give their shed hair in exchange for vessels, and sell it in the market), but had to stop working after this surgery. She has had high blood pressure since her surgery. She has also been complaining of getting seizures on and off, but has not been able to seek treatment for it and takes painkillers for it.

Mostly confined to her bed, with a fan whirring beside her, she is unable to do the most basic things to cool herself. Her elder children who are 11 and 12 years old work outside as hair collectors, while her younger ones who are 10 and 9 years old go to school. She needs their support for every small task in the house, including cooking and bathing.

Though it is sometimes perceived that homes can provide protection, in informal settlements the indoor temperature is often higher than outdoors, a 2022 study showed. In Radha’s case, her disability poses further risk of overheating.

For roughly 17.4 percent of urban population living in informal settlements, the heat stress is far more acute. Houses in informal settlements are rarely built with thermal comfort in mind, leaving residents with limited access to cooling, clean water and heat alerts. Even government affordable housing schemes such as RR Peta continue to overlook basic passive cooling measures such as cross ventilation, insulated roofing and adequate shading, making indoor temperatures as dangerous as outdoors during a heatwave.

Lack of cooling

Vidya bemoans the lack of ventilation in her one-room-kitchen apartment that she shares with her husband and four children (one of her sons lives with relatives).

During summer, her legs swell, and she often gets headaches and back pain, making household work difficult. She said, “I end up sweating continuously while working. Even after sweeping the house, I need to rest for 15 minutes. I have to do all the household work in this heat and through pain. It is so frustrating.”

During the 2024 floods in Vijayawada when RR Peta was affected, Vidya’s family’s washing machine, fridge, and air cooler got destroyed, and her family cannot afford to repair them, increasing her workload considerably.

“Very few informal settlements have cooling facilities, including a fan. Informal settlements are built in areas where there is very little tree cover. They have less access to safe drinking water too. All these result in a spiral of heat stress and some form of morbidity,” said Harsh (he uses one name), a public health physician, part of The 12th September Movement, a group of health workers from the global south exploring interactions of politics, economy, climate change and health.

Access to quality healthcare limited

Krishna (name changed) is 35 years old, has a heart condition and underwent a heart valve surgery in a private hospital three years ago. Now he is no longer able to work and his wife supports the family, working as a hair collector.

“Every six months, I visit a private hospital for a check up. We are barely able to save the money for this check up. Recently when I questioned the hospital staff on some tests that were too expensive, they insulted me and threw files on my face,” he said. He is still paying debt for the surgery, despite it being covered under Aarogyasri, the state health insurance. The insurance covered a large portion of the costs, but he still had to shell out Rs 2 lakh out of pocket.

When asked if he is able to eat vegetables and fruits (as the government public health advice prescribes for extreme heat), he said that the family is not even able to eat three square meals a day, let alone a healthy meal. “Most days we are eating rice and pickles,” he said. His wife barely makes Rs 8,500 a month.

In the summer, he often gets out before noon, even taking a lunch box, to avoid the heat inside his house. “I feel tense during the heat inside the house. Like something (adverse) will happen.”

Harsh said that limited access to affordable quality healthcare, and in some cases any form of healthcare altogether, is another factor that affects those in low-income settlements.

Veena is a 59-year-old widow, and has a disability because of polio during her childhood. She lives in Vambay colony, an informal settlement in Vijayawada (a mix of self-constructed semi pucca houses and government resettlement colony). She moves around on a small plank with four wheels like many physically disabled persons in the country. She begs for a living outside temples and schools.

All her health problems have come to a head since the past few years. She had pain in the chest and was taken to Vijayawada General Hospital two years ago for which she was advised to undergo surgery. She has not gone through with it as it's too expensive, and she was not told about insurance. She is now going every week to the hospital for check ups and medicines. She also has diabetes and is taking treatment from who she calls “sugar doctor” in Vijayawada. She has a chronic skin condition which makes her skin itchy, which exacerbates during the heat. “I feel someone is poking me with needles during extreme heat,” she said.

Even Vidya’s treatment is barely affordable since she stopped working outside. The household depends largely on her husband Srinivas’s income of Rs 10,000 as an autorickshaw driver. She said, “When summer starts, I feel this fear. My heart starts palpitating sometimes. What problems are waiting for me in these months? When will this end?”

This story is republished with permission from IndiaSpend, a data-driven, public-interest journalism non-profit. It has been lightly edited for style and clarity. All images courtesy Shivam Bharadwaj.

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