Decoding the Urban Heat Stress among Indian cities

May 23, 2024

Research direction: Anumita Roychowdhury
Authors: Avikal Somvanshi and Sharanjeet Kaur

Center for Science and Environment, May 2024

Even as unprecedented heat waves lashed Indian cities worsening the urban heat island effects this summer, there are far deeper and longer term evidences on the nature of this changing trend impacting the Indian mega cities.

The new analysis by the Centre for Science and Environment (CSE) shows that the heat stress is not just about rising temperature. It is a deadly combination of air temperature, land surface temperature and relative humidity that adversely impact the thermal discomfort and heat stress in cities.

Even if there is variation in air temperature across climatic zones with some parts recording even a decline, the other two factors – relative humidity and land surface temperature combine to enhance discomfort and heat related disease burden. According to the U.S. National Weather Service, the heat index is a measure of how hot it really feels when humidity is factored in with the actual temperature. It is considered that a heat index of 41°C is dangerous to human health.