You can't go out, you can't stay in.
Each June, Delhi's official thermometers offer a number — 43.5 degrees Celsius — that the city's poorest residents know, in their bodies, to be a fiction. Thermal imaging conducted by Greenpeace India reveals surface temperatures reaching 64 degrees on the streets where vendors and laborers spend their days, exposing a 20-degree gap between what is measured and what is endured. The heat does not fall equally: shade, trees, and the ability to stay indoors are distributed along the same fault lines as wealth, making extreme temperature not merely a meteorological event but a social one. In a city where a single tree can mean the difference between function and organ failure, the question of who gets to stand in the shade is, finally, a question of justice.
- Surface temperatures on Delhi's streets are reaching 64°C — more than 20 degrees hotter than official air readings — placing outdoor workers in conditions that can cause confusion, seizures, and organ failure within hours.
- Street vendors like Sanjana Ben sit centimeters from ground surfaces exceeding 57°C, while laborers like Mohammad Mahfouz Alam describe heat pressing from below and above simultaneously, with no relief between sunrise and sleep.
- Government advisories to avoid midday outdoor work between 10:30am and 3pm are medically sound but practically meaningless for daily-wage earners who have no income if they do not appear.
- Thermal imaging lays bare the inequality: a few meters of shade beneath a tree drops temperatures by nearly 25 degrees, yet urban tree removal and absent shade infrastructure continue to strip that relief from the most exposed neighborhoods.
- Inside homes in lower-income areas, temperatures barely fall below those outside — ceiling fans recycle hot air, windows are absent, and residents report chronic sleeplessness, nausea, and a daily life reorganized entirely around the heat.
Delhi's official temperature on a June afternoon reads 43.5 degrees Celsius. But when a Greenpeace India thermal imaging team moved through the city measuring surface temperatures rather than air temperatures, they found something the weather service does not announce: roads, concrete, and metal surfaces reaching 64 degrees — more than 20 degrees hotter than the official figure, and far beyond what the human body can safely absorb.
The gap matters most to those who cannot escape it. At the IIT flyover in south Delhi, the camera recorded 64 degrees in direct sunlight where motorcyclists idle, dropping to just under 40 degrees beneath a nearby tree — a difference of nearly 25 degrees across less than three meters. Researcher Nibedita Saha noted the obvious: that one tree can mean everything. Dr. A Fathahudeen, a pulmonologist, explained what prolonged exposure above 40 degrees does to the human body — heat exhaustion first, then confusion, then seizures, then organ failure. His advice to avoid midday sun assumes a choice that Delhi's poor simply do not have.
At the Red Fort market, street vendor Sanjana Ben sits on a thin cushion on pavement the camera reads at 57 degrees. Her face registers 40 degrees. She described her vision blurring and her head spinning, standing briefly when the ground becomes unbearable before sitting again because there is no other option. Nearby, footwear seller Mohammad Mahfouz Alam described heat arriving from every direction at once, exhaustion that follows him home, and nights spent sleepless under a fan that moves only hot air. He pointed to the tree behind his stall and said that without it, everything would be over.
In the east Delhi neighborhood of Sundar Nagri, two siblings have been keeping a handwritten heat register for two weeks, documenting how the crisis is reshaping ordinary life. Their two-room home offers almost no relief — surfaces inside hover near 40 degrees, there is no window for ventilation, and the ceiling fan recycles heat rather than dispersing it. Kajal described nausea and the impossible bind of being unable to go out or stay in. Her brother Abhishek read from his register: routines disrupted, sleep lost, his mother visibly more exhausted each day, mornings made unbearable when the fan is switched off for cooking.
What the thermal images reveal, collectively, is that urban heat is not evenly distributed — it pools where pavement replaces trees, where walls trap air, where poverty removes the option of retreat. Shade and vegetation are not amenities but survival infrastructure, and the people most exposed to the city's true temperatures are precisely those with the least power to demand anything different.
Delhi's official thermometer reads 43.5 degrees Celsius on a June afternoon, but that number tells only part of the story. When a thermal camera sweeps across the city's streets—the roads, the concrete, the metal surfaces where people work—it records something far more brutal: temperatures climbing to 64 degrees, a gap of more than 20 degrees that separates what the weather service announces from what the human body actually endures.
The distinction matters because it explains why stepping outside feels like walking into a furnace, why a few feet of shade can mean the difference between bearable and unbearable, and why the poorest residents of India's capital face a heat crisis that the official numbers simply do not capture. A thermal imaging team from Greenpeace India spent a day documenting this gap, moving through the city with equipment that measures surface temperature rather than air temperature. What they found was a portrait of inequality written in degrees.
At the IIT flyover in south Delhi, one of the city's busiest traffic junctions, the camera recorded 42 degrees in the shade beneath the overpass. Step into direct sunlight where motorcyclists idle at red lights, and the reading jumped to 64 degrees. Move less than three meters to stand under a tree, and it fell to just under 40 degrees. "That's the difference just one tree can make," said Nibedita Saha, the Greenpeace researcher holding the camera. The relief was immediate. The human body does not need a lecture on thermodynamics to understand what those numbers mean.
Dr. A Fathahudeen, a pulmonologist, explained the mechanics of heat illness in clinical terms. The human core temperature sits at 37 degrees. When external heat pushes the body above 40 degrees for prolonged periods, normal function breaks down. Heat exhaustion arrives first—extreme sweating, headaches, fatigue. In worse cases, confusion sets in, then seizures. Without urgent treatment, organ failure follows, and then death. The advice he offers is straightforward: drink water constantly, wear light loose clothing, use an umbrella. The government, he suggested, should ban outdoor labor between 10:30 in the morning and 3 in the afternoon. But that recommendation assumes a choice that Delhi's poor do not have.
At the Red Fort in Old Delhi, where narrow lanes open onto markets and shrines, street vendors had set up their stalls despite the heat. Sanjana Ben sells dried fruits from the pavement, sitting on a thin cushion on the ground. The thermal camera recorded 40 degrees on her face but 51.4 degrees at ground level, climbing to 57 degrees just a few centimeters away. "At times my head spins and my vision blurs," she told the BBC. "When the ground feels very hot, I stand up for a bit. But how long can I do that, so I sit down again." Nearby, Mohammad Mahfouz Alam sells footwear from a stall. He described heat rising from below and pressing down from above simultaneously, with no relief between sunrise and sleep. "There's no relief day or night. I feel listless, my legs hurt. I reach home exhausted. Even after I take a bath, I cannot sleep. The fan blows hot air and I keep tossing and turning in bed." He pointed to a tree behind his stall. "If this tree wasn't there, it'll be impossible for me to be here. The day this tree is gone, everything will be over."
In Sundar Nagri, a lower-middle-class neighborhood in east Delhi, two siblings named Abhishek and Kajal have been keeping what they call a "heat register" for the past two weeks, documenting how extreme temperatures are reshaping their lives. Outside their home, the thermal camera read 42 degrees. Inside their two-room house, the temperature barely dropped—hovering around 40 degrees on plates and glasses on a shelf. There was no window for heat to escape, only a ceiling fan recycling hot air. "When it's very hot, I feel nauseous," Kajal said. "You can't go out, you can't stay in." Abhishek read from his register: "This week's heat has changed our daily routines. Everyone returns home late and no-one is sleeping well. In the mornings, the fan is switched off during cooking and the heat becomes unbearable. My sister finds it hard to do her chores. My mother looks more tired than ever." At night, he wrote, he cuts his hair short, washes his face repeatedly, removes his shirt, but still cannot sleep. "Outside, there's at least a breeze, inside it feels like I'm standing next to an oven."
The thermal images tell a story that official temperature readings obscure: that heat in cities is not evenly distributed, that shade and vegetation are not luxuries but necessities, and that the people most exposed to extreme temperatures are those least able to escape them. A tree can drop the temperature by 20 degrees. A window can mean the difference between sleep and insomnia. And a job that requires sitting in the sun all day, because there is no other way to earn, becomes a slow accumulation of damage that no amount of water or loose clothing can fully prevent.
Notable Quotes
If this tree wasn't there, it'll be impossible for me to be here. The day this tree is gone, everything will be over.— Mohammad Mahfouz Alam, footwear vendor
At times my head spins and my vision blurs. When the ground feels very hot, I stand up for a bit. But how long can I do that, so I sit down again.— Sanjana Ben, dried fruit vendor
The Hearth Conversation Another angle on the story
Why does the thermal camera reading matter more than what the weather service reports?
Because the weather service measures air temperature under standard conditions—basically, the temperature in the shade at a certain height. But people don't live in the air. They stand on concrete, sit on metal benches, work on asphalt. Those surfaces absorb and radiate heat. A street vendor isn't experiencing 43 degrees; they're experiencing the 57 degrees radiating from the ground they're sitting on, plus the sun beating down. The gap between those numbers is where the real suffering lives.
The doctor mentioned that organ failure can happen. Is that actually a risk for these street vendors?
Yes, if the exposure is prolonged enough and the person doesn't get relief. Heat exhaustion is the first stage—sweating, headaches, confusion. If someone can't get to shade or cool water, if they keep working because they need the money, the body's core temperature keeps rising. At a certain point, the organs start to fail. It's not theoretical. It happens every summer in Delhi.
But people have been living in Delhi for centuries. Why is this suddenly a crisis?
Because the city has changed. One vendor mentioned that seasons have become erratic—summer is hotter, longer, more intense. And the city itself has been paved over. Trees are cut down for development. Concrete and asphalt replace vegetation. That tree behind the footwear vendor's stall—he said if it's gone, he can't work there anymore. That's not metaphorical. That tree is keeping him alive.
The government's advice to not work between 10:30 and 3 seems reasonable. Why can't people just follow it?
Because they're poor. If you don't work those hours, you don't earn. There's no safety net, no paid leave, no employer who will pay you to stay home. The advice assumes you have a choice. These vendors don't.
What struck you most about the heat register that Abhishek was keeping?
That he was documenting it at all. He's not a scientist or a journalist. He's just a young man in a neighborhood where the heat is so severe that he felt compelled to write down how it's destroying his family's sleep, his mother's energy, his sister's ability to do basic tasks. That register is a record of a life becoming uninhabitable. And it's only June.