A wave of record-setting heat waves, beginning in March, have led to new Government guidelines for emergency cooling including measures like heat stroke rooms. Even so, public health  experts are only beginning to grapple with the multiple ways in which heatwaves can kill – and map out mitigating measures for both healthy people as well as the more vulnerable, including people with chronic diseases. 

Under a mid-day blazing sun on a busy Delhi road, Monu Kumar Yadav tends to his cart. There’s little shade. He’s selling bael sharbat or stone apple juice, a popular summer drink. It’s 41°C but Yadav, who says he’s here from 8am to past 5pm daily, says it’s bearable. It was far worse a week ago, he says.

There have been a series of heatwaves in almost every part of the country since March and these are forecast to continue in the north throughout June. Temperatures have been as much as six degrees or more above normal and touched 50°C in several places. The capital, New Delhi, hit a record high of 49.9° C at two stations. 

Heatwaves coincided with India’s general election held across April, May and June. Hundreds of deaths have been reported, several of these related to the election. Some 33 polling staff died from the heat on the last day of voting in Bihar, Uttar Pradesh and Odisha states, according to Reuters.

Experts in the government had forecast the heatwaves and prepared response plans. This is in addition to the heat action plans in dozens of Indian cities. But local administrations and communities were seemingly caught unaware. 

Climate scientists have calculated that heat waves will only get worse with the record amount of carbon dioxide and other greenhouse gases being emitted. 

The heat wave alerts began as early as February. From early March onwards, forecasts warned temperatures could be more than 5° C above normal in parts of the country. The Indian Meteorological Department (IMD) has also warned of hotter temperatures and longer heatwaves this year.

A fortnight later the Election Commission of India announced the longest voting schedule in decades lasting 44 days; longer, if the campaign and counting days are included. 

India’s longest heatwave?

April’s heat was alarming with a rare heatwave alert in the southern coastal state of Kerala. In eastern India, deaths began to be reported. But it was about to get a whole lot worse in May, in the north. 

A new study by ClimaMeter, a global group of scientists who provide a climate context for weather extremes, shows May’s heatwave was 1.5°C hotter than any other ever recorded in India. 

Delhi’s power demand touched a record high, its water supply ran low. The local government announced it would fine anyone wasting water, for instance washing cars with water pipes or letting tanks overflow.

Separately, the IMD told Health Policy Watch that several states in north India saw an unusually long stretch of heatwave days. The normal for May is three days for places like Delhi, and a few more for places like the desert state of Rajasthan and Madhya Pradesh in central India. 

IMD forecast the number of days could be as much as four to eight days above normal. But it turned out to be far more at about 15 days. Officials that HPW spoke with couldn’t recall a similar event in recent years though they are yet to analyse whether this is the longest stretch ever on record.  

The spell was broken by some storms and rain in early June but the heatwaves are forecast to continue in north India. 

With hotter nights, the danger is shifting indoors. The human body gets little chance to recover from the day’s heat and cool down which hits health and productivity at a “very large scale,” Sharma adds. 

Heat and NCDs

Extreme heat may be a direct trigger for fatal conditions, even in the healthiest person.  The most direct impacts involve deaths from heat stroke – when the body’s core temperature shoots up beyond normal temperatures of 36.8°C . If temperatures cross 42°C or 107.6°F, cellular damage and cardiac, respiratory and kidney failure begin to occur. 

But heat can also can exacerbate pre-existing noncommunicable diseases in older people, other groups with chronic conditions, and newborns lacking poor heat regulation, also leading to death. At least 605 people died of heart attacks out of almost 25,000 “suspected” heat stroke cases in India between March and May according to government data. 

In earlier years, experts have pointed out that heat-related deaths have been under-reported, insofar as many of those who perished also suffered from other types of non-communicable diseases (NCDs), such as cardiovascular or respiratory conditions – to which their deaths were attributed.

But this season the number of heat-related deaths being reported has been frequent and high -signalling at least a new awareness of the ways in which heat can exacerbate pre-existing NCDs. Several of these have been reported from the election. However, the data remains plagued by discrepancies and confusion – which are understandable in light of the complexity of the diverse impacts of heat on healthy and more vulnerable groups.  

As of 1 June, the National Centre for Disease Control (NCDC) reported 56 deaths. But that excluded Uttar Pradesh, a northern state with a population larger than the UK, France, and Germany combined, where 166 deaths had been reported as of May.

Election commission should bookmark this pic and use it as a reminder before conducting future election during peak summers. The elderly man collapsed and died at the polling booth in Ballia, UP. pic.twitter.com/AjBg04RRbz

— Piyush Rai (@Benarasiyaa) June 1, 2024

About 141 deaths suspected to be heat-related were reported from the eastern, coastal state of Odisha as the polls ended. However, officials said post-mortems and investigations had shown less than a fifth to be due to heatstroke, as such.  

The capital, Delhi, too saw many deaths (24) in the last week of May, and over 120 in Rajasthan. There, in one city, newborn babies were put on dialysis because of dehydration leading to an increase in sodium levels. 

With such a devastating impact, Rajasthan’s top court called for heatwaves to be categorised as “national calamities” which would enable emergency relief as with other natural disasters, though there’s no decision on that yet.  

‘Cooling, cooling, cooling’

The response to the heatwave crisis has broadly been at two levels. Met and health experts within the government have been putting out warnings and advisories. 

Health advisories include detailed guidelines, webinars, social media posts and other outreach efforts; there was even a meeting held by Prime Minister Narendra Modi where he called for a whole of government approach and hospitals to be adequately prepared. 

Health is a state subject in India, which means that the central government can put out advisories but the states decide their policy and what to implement. One such advisory titled ‘Emergency Cooling for Severe Health Related Illnesses’ was released in March 2024. 

In February, the National Disaster Management Authority held a workshop where preparations for this year’s heatwaves were discussed by health, disaster management, met, and climate experts in the government. It showed how training had begun as early as January, that there should be a decentralised approach involving local communities and health infrastructure should be strengthened, for instance establishing cooling centres in public buildings and spaces. 

For the first time this year, such advisories called for heat stroke rooms. These are essentially places set up at healthcare centres to rapidly cool a person suffering from heat stroke, a potentially fatal condition. Doctors point out the main treatment for heat stroke or heat exhaustion is “cooling, cooling, cooling.” 

The mortality rate for delayed treatment is about 80%, but with early identification and rapid cooling, it can be as low as 10%. Symptoms of a heat stroke include a temperature of 40.5°C/104.9°F or more, throbbing headache, no sweating, and red hot dry skin among others. 

The idea is to bring the body temperature down to 39°C/102.2°F as quickly as possible. The methods prescribed include immersing a person in an ice bath or very cold water, placing ice packs on them, using wet towels, and rushing them to the hospital. 

But to what extent have these guidelines and advisories been implemented at the grassroots level? There is little data available about how many health centres, the most basic and widely spread health care facilities, in rural and urban areas were equipped to identify and treat heat stroke patients. The heat stroke room was proposed last year and implemented this season, according to a source. It is meant to be set up at all healthcare facilities but it’s unclear how many were done. 

Towards the end of May, the central health ministry asked states to take “proactive measures to prevent devastating incidents caused by extreme heat.” A substantive press note was issued two days after the election result. 

Assessing heatwave risks to health

At least three types of temperature readings may be considered for hyperlocal responses. An understanding of these can help people and authorities work out what to do in a house, in schools or offices, at construction sites, in marketplaces, and of course at public gatherings.

The first is the conventional meterological temperature. Several places and meteorological stations in the arid plains of India have crossed 50°C. Around this time, swathes of the north were forecast at 45-50°. Such temperatures, even for one day, can be fatal, depending on the person’s age, co-morbidities, and other factors. 

The scond is urban heat island temperatures. A study done in April used a thermal camera and it shows how built-up or paved areas can be much hotter than the official temperatures. In vivid visuals, these illustrate what climate scientists including the IPCC have called the urban heat island effect. If the temperature was about 40°C according to standard, official readings, it could be as high as 50-59°C depending on concrete or tarred places that trap heat.

Our team used a thermal camera to capture temperature readings of a few street markets in Delhi. The highest reading recorded was 59°C. It's hard to even imagine how our street vendors are dealing with the heatwave.

Pc @selomigarnaik pic.twitter.com/aEBSpFWzpw

— Avinash Chanchal (@avinashchanchl) April 30, 2024

The third is the ‘feels like’ temperature. Experts warn of another danger, particularly for low-income households.

Anshu Sharma is co-founder of SEEDS, which works with people, particularly in vulnerable communities, to build their resilience to disasters and climate change impacts. He warns that wet bulb temperatures – a factor of heat and humidity – must be monitored to provide relief.

“While temperatures will drop once the Monsoon arrives, the suffering will not go away. Indexed heat, with the addition of humidity, will make it feel worse than the current dry heat, with indexed temperatures expected to go well above 50°C,” says Sharma.

“This year’s heatwaves, characterised by hotter days, much hotter than normal nights, and longer duration of heatwaves have hit people harder than usual. Nights, especially during power cuts, are particularly unbearable for those who cannot afford air conditioning and power backups.”

Many causes or one main cause?

In eastern India, the heatwaves may have been exacerbated by anti-cyclonic circulation and the absence of thunderstorms during April, and in the northwest, the absence of western disturbances (bringing storms and rain) during May. The El Nino phenomenon has also been blamed. This is the Pacific climate pattern which tends to cause hot and dry weather in Asia and heavier rain in parts of the Americas. 

The biggest cause, however, is climate change. World Weather Attribution (WWA), at the Grantham Institute in Imperial College London, says that the heatwaves in the last two years became 30 times more likely and hotter because of human-induced climate change. 

Dr Mariam Zachariah, a WWA Researcher, told HPW, “While it is likely the additional heat from El Nino, a naturally occurring climate phenomenon, helped push summer temperature extremes in some regions of India to cross 50C, such episodes will become more frequent in India as the climate warms, regardless of El Nino.” 

Monu Yadav doesn’t know what makes the heat worse than earlier years but out on the roads for eight to 10 hours a day, he knows for sure that it’s hotter than anything else he’s experienced in Delhi. 

With greenhouse gas (GHGs) emissions rising faster than ever to record levels, heatwaves will get worse, but the response needs to be better. Cutting GHGs is vital, as are SOS cooling solutions for people.

Image Credits: Chetan Bhattacharji, Webinar/Ministry of Webinar on Clinical Aspects of Heat-Related Illnesses – National Programme on Climate Change and Human Health, MoHFW., Webinar on Clinical Aspects of Heat-Related Illnesses: National Programme on Climate Change and Human Health, MoHFW., World Weather Attribution.