In New Delhi’s Sundar Nagri neighborhood, one of the city’s most densely populated and economically disadvantaged areas, residents are confronting dangerously high indoor temperatures that persist long after sunset. Campaigners working with Greenpeace India have begun documenting the extreme heat conditions inside homes, aiming to push for stronger governmental protections for vulnerable communities during increasingly severe heatwaves.
Durga Devi, 45, spends her days working in a factory without access to fans and returns home each evening to a poorly ventilated room that remains uncomfortably hot throughout the night. She has recorded temperatures inside her one-room house reaching as high as 45 degrees Celsius after dark. The concrete structures and narrow lanes, typical of informal settlements in this metropolis of 30 million people, trap heat during daylight hours and release it slowly overnight, leaving residents with little respite.
Devi’s son, 21-year-old student Abhishek, is among the 20 families participating in the initiative to measure and track heat levels using thermal cameras and heat diaries. His data indicates indoor and neighborhood temperatures significantly higher than those reported by official meteorological stations. On paved surfaces outside their home, temperatures have exceeded 60 degrees Celsius during the hottest parts of the day. Indoor readings taken during a recent visit showed room temperatures at 32 degrees and kitchen walls rising to 37 degrees Celsius.
“Heat doesn’t end when the temperature outside falls,” said Deepali Tonk, a Greenpeace India organizer involved in the project. She emphasized that these homes offer no real haven from the heat, leaving residents vulnerable through the night. The campaign intends to collect further data and personal accounts through July before filing a legal petition seeking enhanced heat protection measures and comprehensive action plans.
Current heat action programs across India vary widely by state and primarily focus on short-term interventions such as issuing heat alerts, modifying school and work schedules, providing water, and setting up temporary cooling centers. However, they rarely address the underlying issues related to substandard housing, urban heat retention, or protections for informal laborers who often have no choice but to work in extreme conditions.
Residents like 19-year-old student Arshi Qureshi highlight the limitations of existing policies. “Officials come to count fans or rooms, but we are not just numbers. We live this every day,” she said, underscoring the need for more individualized and sustained responses.
India is experiencing a rise in extreme heat episodes, linked to climate change, with New Delhi frequently reaching or surpassing historic high temperatures. The India Meteorological Department recently recorded the city’s highest May night-time temperature in 14 years—31.9 degrees Celsius in May 2026. Heat-related mortality data remain limited, with official statistics often excluding deaths indirectly caused by heat stress, such as cardiac events.
A study by researchers at the University of California, Berkeley, estimates significant underreporting of heat-related deaths in India. Their analysis suggests single days of extreme heat may cause roughly 3,400 additional deaths nationally, with prolonged heatwaves potentially resulting in nearly 30,000 excess fatalities. “What you cannot measure, you cannot manage,” said Ashok Gadgil, co-author of the study, stressing the need for localized data to guide effective interventions.
In Sundar Nagri, residents like Raja, a 21-year-old vegetable seller and political science student, and his mother Madhuri Devi describe worsening conditions each summer. Madhuri has experienced severe physical distress from cooking over indoor stoves amid the heat. Their hope is that by sharing their experiences and data, the government will develop better strategies to protect those living in some of India’s most heat-vulnerable environments.