Delhi's Surfaces Reach 64C, Far Above Air Temperature

This large difference exists because the two methods measure different things. The IMD records the temperature of the air under standard conditions, while thermal cameras measure the temperature of physical surfaces. On hot days, roads, concrete and vehicles become much hotter than the air around them, and they radiate this heat back, adding to the load on the human body. The effect is strongest in crowded urban areas with little shade or greenery. The contrast can be sharp: one surface measured 61C but dropped to 39.8C just a few feet away under a tree.

The health risks are serious. Dr A Fathahudeen, a lung doctor, explained that the body's core temperature is 37C, and that long exposure to extreme heat can push it higher. Above 40C, he said, the body stops working normally, causing exhaustion, headaches and, in severe cases, confusion or organ failure. He advised people to drink water often, wear loose, light-coloured clothes, and avoid outdoor work in the early afternoon. But Delhi's poorest cannot afford to stop. Street vendors said they must keep working, and many homes stayed near 40C inside.