Climate change drives rise in dangerous humid heat days across India: Analysis

A new analysis by Climate Central says India has seen a significant rise in dangerous humid heat days, increasing from an average of 101 annually in the 1970s to 141 between 2016 and 2025, largely due to human-caused climate change

New Delhi: India has witnessed an increase in dangerous humid heat days from an average of 101 days per year during the 1970s to 141 days per year between 2016 and 2025, according to a new analysis.

A dangerous humid heat day is when the daily maximum wet-bulb temperature — a measure that combines heat and humidity to show how stressful the environment actually feels to the human body — is 25 degrees Celsius or higher.

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The rise in the number of such days is dangerous, as humid heat can compromise the body’s main cooling mechanism (sweating) and lead to a range of serious and even fatal heat-related illnesses.

The analysis was released on Wednesday by Climate Central, an independent group of scientists and communicators who research and report facts about the changing climate and how it affects people’s lives.

India is not alone in experiencing an increase in the number of dangerous humid heat days.

According to the analysis, these days have more than doubled globally, from 10 days per year during the 1970s to 23 days per year between 2016 and 2025.

The largest increases have occurred in tropical humid regions, where wet-bulb temperatures are typically higher and are closer to the dangerous threshold.

It added that nearly two-thirds (64 per cent) of global dangerous humid heat days since 1970 can be attributed to human-caused climate change.

“Climate change has gone from a minor contributor of dangerous humid heat days to the primary driver. In some parts of the world, humid heat that once would have been rare or nearly impossible without climate change is now a defining feature, putting the lives of millions at risk,” said the analysis.