5 dead in Chennai IAF event: When does heat turn fatal, how should it be dealt with?

A senior police official told The Indian Express: “Over 150 people have received first aid in various parts of the city due to the dehydration and stress they faced. One death was reported on the beach, another near Napier Bridge. Other victims died on their way back home at different places. It was not a stampede situation at one particular place.”

When does heat become deadly for humans, what can be done for prevention? We explain.

When does heat become dangerous?

Attendees of the IAF event said water and medical assistance were not easily available at the beach, despite temperatures as high as 36 degrees Celsius.

Similar cases of deaths or heat strokes have happened in the past due to multiple factors. In April 2023, a government award function held in an open space in Navi Mumbai led to the deaths of 13 people. Then too, the maximum temperature hovered around the 30-35 degree Celsius range.

However, temperature alone is not responsible for deadly conditions — it is actually the combination of high temperature and high humidity, referred to as “wet bulb” temperature. High moisture content in the atmosphere makes it difficult for sweat to evaporate and bodies to cool down, resulting in the body’s internal temperature sharply increasing. It is often fatal.

Being in high temperature and high humidity conditions for a long period can further test the body’s capacity to cope. In Chennai, the higher-than-anticipated crowd size made it difficult for people to leave the venue in time, and the administration appeared unprepared to facilitate their movement. The metro and train stations, as well as the roads near the beach, saw thousands of people attempt to use transport services during a short period of time.

Passengers board a train at the Velachery railway station to depart for an air show on the 92nd Indian Air Force (IAF) Day at the Marina Beach, in Chennai, Sunday, Oct. 6, 2024. (PTI Photo)

In the case of Navi Mumbai, factors such as long exposure to heat in open and shadeless ground and physical exertion due to people travelling a long distance — present in Chennai as well — played a role.

How should heat and high humidity be dealt with at public events?

For individuals at such events, it is imperative to be hydrated and drink fluids such as lassi, lemon water, buttermilk or ORS to maintain electrolyte levels, even when one is not thirsty. Drinks such as alcohol, tea, coffee and carbonated soft drinks can dehydrate a person and should be avoided at such times.

Lightweight, light-coloured, loose, and porous cotton clothes should be worn. It is important to avoid Sun exposure for long hours and to stand under shade whenever possible. Goggles and umbrellas should be carried for protection.

Joy Merwin Monteiro, a Climate Scientist working at the Department of Earth and Climate Science at IISER, Pune, earlier wrote in The Indian Express that talks of wet bulb temperature often focus on climate change and rising temperature, which “subtly shifts the responsibility of action from the local to the transnational arena.”

While global climate change is an important concern, to avoid such incidents, “understanding the factors that increase vulnerability to heatwaves puts the onus on local actors, who have to provide better sanitation facilities, protect the elderly and those with cardiac conditions, and reduce the incidence of diabetes in the population,” he wrote. Adequate administrative arrangements need to be made to protect vulnerable groups in particular.