India's heatwave pushes wet-bulb temperatures toward human survival limits
India's heatwave isn't just about high temperatures: there's a sneaky metric called "wet-bulb temperature" that mixes heat and humidity.
When this number climbs, sweating stops working as a cooling system for our bodies.
Right now, several cities are getting dangerously close to levels where it's tough for humans to survive outdoors.
Mumbai Chennai workers face wet-bulb danger
Wet-bulb temperatures hit hardest in humid cities like Mumbai and Chennai: a sticky 38 Celsius there can actually be riskier than a dry 45 Celsius elsewhere.
Research shows the human body can struggle at wet-bulb temperatures as low as 31-32 Celsius, lower than what was once thought safe.
Outdoor workers are most at risk since they often don't have access to air conditioning or shade, so the IMD now uses percentile-based thresholds in its alerts to help flag dangerous heat conditions.