The heat vulnerability map shows “hot spots” in central India. Credit: Azhar, G. et al
This summer extreme heat topping more than 43 degrees Celsius has swept across southern India, echoing the region’s deadly 2015 heat wave, which is thought to have killed more than 2,000 people. While worldwide heatwaves are predicted to become more extreme, there is some debate about how this will affect India1.

For the first time researchers have now developed a model to assess and rank heat vulnerability in 640 Indian districts.

Analysis of the Heat Vulnerability Index (HVI) identified 10 districts in the very high risk category and 97 as high risk. Mapping showed that these are mostly located in central India and that rural areas are slightly more vulnerable than urban areas2.

“With a higher tribal population, these [central Indian] states have been at the lower end of various health, education, economic and population growth indicators,” the authors wrote. “These land-locked, high HVI districts in the North and Central Indian plains are classically known as the ‘heat belt’.”

Effective strategies to tackle heat vulnerability

The authors hope to help focus targeted health and adaptation efforts, which may include public warnings about heat waves and heat-protective housing design. “Simple prevention efforts can save lives and are extremely cost effective,” says author Gulrez Azhar.

He says the researchers pored over previously published research on what determines heat vulnerability and identified key indicators such as – age extremes, poverty, working in the outdoors, poor health and social status. They then collected datasets on as many of these variables as possible including from the most recent census, health reports, and satellite remote-sensing data.

The research was an international collaboration between United States-based institutions, the Rand Corporation, the Rollins School of Public Health, and the Indian Institute of Public Health, and the Public Health Foundation of India.

Their results showed that vulnerability was correlated with rural areas, low rates of literacy, poor access to water and sanitation, and a lack of facilities within households.

Azhar notes that “these correlations highlight the importance of interventions against other associated diseases such as gastrointestinal diseases in children and water-borne illnesses.”