INDIA
Exposure to extreme heat and cold temperature is leading to additional preventable deaths, new 19-year study suggests
There’s no time to be lost to reduce deaths from heatwaves and extreme cold in India, where study took place
Urgent action must be taken to reduce the ever-rising number of people killed by extreme temperatures in India, say the authors of a new 19-year study which found that 20,000 people died from heatstroke in the last two decades. Cold exposure claimed another 15,000 lives.
Findings published today in the peer-reviewed journal Temperature, also revealed that deaths from heatstroke are more common in men of working age and identified the states that are hotspots for deaths from heatstroke and from hypothermia and other conditions fuelled by the cold.
There is an upward moving, increasing trend in terms of mortality due to heatstroke and exposure to cold in India, with glaring variation across states.
“Deaths due to heatstroke is more significant, compared to deaths due to cold exposure, albeit recording an upward trend,” says the study’s lead author Professor Pradeep Guin, whose research at the O.P Jindal Global University (JGU), in Sonipat, India, is at the intersection of climate change, environment, health, politics and governance.
Hundreds of people die from the heat or cold each year in India and many of these deaths are avoidable.
Last year, Mungeshpur, in Delhi, recorded highest-ever summer temperature in India, at 52.9°C (126.1°F). Every summer, in India, we hear about heat-related deaths, which is avoidable. Similarly, some parts of the country – not the traditionally colder states – report deaths due to cold waves, which can be controlled. However, there needs to be adequate infrastructural and social safety-net support, the authors state.
“With an intense heatwave forecast to hit most of the country this summer and extreme weather events becoming more frequent around the globe as the world warms, there is no time to be lost in raising awareness about the dangers of extreme temperatures and putting in place measures to reduce their impact.
“Support systems exist, but more needs to be done,” Professor Guin adds.
There is growing recognition of the harm excessive temperatures can do to health, however previous research has focused on developed nations and one-off events, such as heatwaves, rather than looking at low and middle-income countries and extreme temperatures that are starting to recur year after year.
India’s size and geography make it prone to extremes of heat and cold and, when designing measures to keep the population safe, it is important to know which people and places are most at risk.
To identify the people who are most vulnerable to extremes of temperature and the states with the highest death tolls, Professor Guin and a group of scholars from JGU, conducted country-level analysis assessing 19 years (2001–2019) of data, and state-level analysis with 14 years (2001–2014) data.
The separate period of analysis was due to “variability in availability of data”. They sourced most of their data from official data sources, such as the India Meteorological Department (IMD), the National Crime Records Bureau (NCRB), the Reserve Bank of India (RBI), and the Office of the Registrar General and Census Commissioner.
Analysis of temperature data from the Indian Meteorological Department and records of deaths from natural causes showed in India, between 2001 and 2019, there were a minimum of:
19,693 deaths from heatstroke
15,197 deaths from cold exposure
Not all deaths are typically recorded and so the figures may be an underestimate.
Nationally, maximum number of deaths due to both heatstroke and exposure to cold was reported in 2015 alone as:
1,907 deaths due to heatstroke
1,147 due to cold exposure.
Contrary to global evidence, which have found that women tend to be more susceptible to extreme heat, more males in India died due to exposure to extreme temperatures.
During the study period (2001–2019), male deaths compared to female were three to five times higher due to heatstroke, and four to seven times more due to exposure to cold.
People in the age-group of 45-60 were most susceptible to die both due to heatstroke and cold exposure, followed by the elderly (60 and above) and those in between 30-45 years.
“The higher death toll from heatstroke in working-age men may reflect the fact that men are more likely to work outdoors than women,” explains Professor Guin, who is also an expert in public policy.
“Even with improvements in the female labour force participation rate in India in the recent years, there are more men working outside in the open environment to meet their household needs. Physically demanding outdoor work, such as construction work, should be halted during heatwaves and those with other outdoor jobs, such as auto rickshaw drivers and gig economy workers, should be provided with adequate relief measures such as shaded parking areas with provisions for drinking water and toilets. Essentially, those who are working outside are more exposed to extreme heat, thereby the more vulnerable gender to death,” said Professor Guin.
“We believe that the Government should consider offering some form of social support to outdoor workers, particularly low-income workers and those on a daily wage, who may feel they have no option but to turn up to work, whatever the temperature.”
As to why more people died from the cold, despite winters getting warmer, this could be because the change in temperature wasn’t uniform across the country.
“While the average winter temperature is increasing, some parts of India are experiencing new lows,” says Professor Guin. “These states are not used to cold temperatures and so likely don’t have measures in place to deal with them, which could explain why the number of deaths from the cold is rising.”
A separate analysis of state-level data from 2001–2014, indicates that the three most vulnerable states to extreme heat are Andhra Pradesh, Uttar Pradesh, and Punjab.
Andhra Pradesh, on the east coast of Southern India, had the highest death toll from heatstroke followed by Uttar Pradesh and Punjab, in the north of the country.
Uttar Pradesh, Punjab, and Bihar are the top three states in terms of cold exposure mortality.
By conducting this more detailed state-level analysis – which including monitoring other factors, apart from extreme temperature exposure, to explain mortality – the research team was able to demonstrate in large urban populations, where more is spent on health, and other social sectors, there were fewer extreme temperature-related deaths.
Professor Guin adds: “Should it be surprising that most deaths due extreme temperatures are not being reported from traditionally either the hottest or coldest regions in India? This is likely due to higher adaptative mechanisms that help residents survive the harshest of temperature. On the other hand, states which recorded more extreme temperature-related deaths are likely to have lower adaptive mechanisms and need greater infrastructural and social safety-net support.”
Co-author, Professor Nandita Bhan, of the Jindal School of Public Health and Human Development at the JGU, say the results show that there is an urgent need to develop and strengthen action plans for individual states.
“Several states in India are developing heat action plans that can provide relief through innovative built environment initiatives, and these need study as well as scale-up, including expanding cold action plans across more vulnerable states.”
Local and simple language should be used to raise awareness about the danger posed by extreme temperatures. The number and quality of night shelters should be increased and living conditions for homeless people improved. Other measures include providing more shade, by for example, covering bus stops and walkways. The health system must also be better prepared and early warning systems need to be improved.
“In the future, further research and analytics at sub-national levels, including districts will be able to guide district authorities to make localised intervention plans, including improved early warning systems and enhanced welfare programs,” says fellow co-author Keshav Sethi, a doctoral candidate at the Jindal School of Government and Public Policy.
“Collecting and collating data on temperature and mortality for a country the size and scale of India is challenging, and initiatives of state agencies to maintain these data archives is commendable. It allowed researchers like us to test our hypotheses and can lead to evidence-informed policy,” concludes Professor Bhan.
“We are hopeful that our work will lead to a further momentum of collaborations to understand the global and national impacts of climate change on human health.”
The study’s limitations mainly relate to data. The analysis did not include socioeconomic data or information from hospital records and the state-level data only covered 2001 to 2014.
Journal
Temperature
Article Title
Mortality due to heatstroke and exposure to cold: Evidence from India
Shelters at bus stops intended to provide relief from heat can actually result in higher temperatures, UTHealth Houston researchers discover
image:
Kevin Lanza, PhD, assistant professor in the Department of Environmental and Occupational Health Sciences at UTHealth Houston School of Public Health
view moreCredit: UTHealth Houston
Some public transit shelter designs can actually do more harm than good when it comes to shielding from summer temperatures, according to a study led by UTHealth Houston.
The research was published in Transportation Research Part D: Transport and Environment.
Public transit can be more affordable, healthy, and safe than commuting by car. Research supports that public transportation is also better for the environment by limiting emissions and air pollution. According to the American Public Transportation Association, more than two-thirds of transit users in the U.S. walk to the transit stop or station. However, during extreme summer temperatures, transit riders may find taking public transport more difficult.
Shelters installed at transit stops and stations are designed to provide protection from extreme heat, high winds, solar radiation, rain, and snow. But according to Kevin Lanza, PhD, assistant professor in the Department of Environmental and Occupational Health Sciences at UTHealth Houston School of Public Health, no studies have taken ground measurements to determine how shelters and tree shade at bus stops influence heat stress.
“Heat stress is a combination of factors, not just the temperature you see on your phone’s weather app or your car dash,” Lanza said. “Imagine it’s 100 degrees out. If the sun is also strong and hitting you, that continues to heat you up.”
Prolonged exposure to high temperatures, such as when one is waiting for the bus, can lead to heat stroke, which can occur in minutes when the body’s core temperature reaches 104 degrees. The chances of heat stroke increase when high temperatures are accompanied with high humidity.
The study focused on trees and shelters at 17 bus stops in Houston over 13 days when temperatures reached 95 to 103 degrees between July 20, 2023, and Aug. 7, 2023. Researchers used advanced sensors to record wet bulb globe temperature (WBGT), a measure of heat stress that combines air temperature, humidity, wind speed, and solar radiation, in shaded and unshaded areas at bus stops. Taking into account shelter design, tree canopy coverage, and time of day, they determined how shade impacts the heat stress of bus riders.
On average, unshaded areas at bus stops recorded a WBGT of 92.5 degrees, posing a significant heat stress risk. Results found that providing shade at bus stops significantly reduced WBGT. On average, trees lowered WBGT by 5.9 degrees.
Lanza and the team looked into four bus shelter designs. Of the four, a stainless steel frame with glass sides and roof provided the most cooling (5.9 degrees lower). Another design, with an aluminum frame, translucent acrylic walls, and a slightly domed roof, only cooled the air by 1.6 degrees. A third similar design with a larger dome but shallower depth and an overhanging roof cooled the air by 2.9 degrees. However, the team measured temperatures underneath that shelter, when unshaded, to actually be 5.2 degrees higher than unshaded areas outside of shelters.
“Because the enclosed acrylic walls with metal trapped radiation inside the shelter, it was like an oven, making it hotter than outside the shelter,” Lanza said. “Study results can serve as evidence for planting trees at bus stops for maximum cooling, and if shelters are the only option, then being strategic in design.”
Co-authors of the study include Baojiang Chen, PhD, an associate professor of biostatistics at UTHealth Houston School of Public Health, and Sara Ernst and Katie Walkins, former journalists at Houston Public Media.
Media Inquiries: 713-500-3030
Journal
Transportation Research Part D Transport and Environment
