New Delhi:

India experienced 536 heatwave days this summer, the highest in 14 years, with the northwestern region recording its warmest June last month since 1901, the India Meteorological Department (IMD) said on Monday.

The country recorded 181 heatwave days in June, the highest after 177 days in 2010, IMD Director General Mrutyunjay Mohapatra said at a virtual press conference.

“In 2024 summer, India experienced a total of 536 heatwave days, the highest after 2010 (578 days). In June, it experienced 181 heatwave days, surpassing 2010 (177 days),” he added.

Mohapatra said the monthly average maximum temperature in northwest India settled at 38.02 degrees Celsius, 1.96 degrees Celsius above normal. The average minimum temperature stood at 25.44 degrees Celsius, 1.35 degrees Celsius above normal.

Northwest India recorded a mean temperature of 31.73 degrees Celsius in June, 1.65 degrees Celsius above normal and the highest since 1901.

Northeast India recorded a 33-per cent rainfall deficit in June, which Mohapatra attributed to the sluggish advance of monsoon over the northern and eastern parts of the country due to a lack of weather systems.

“Only one low-pressure area developed towards the end of June. Normally, we get three low-pressure systems. The Madden-Julian Oscillation was not favourable and therefore, we could not get enhanced convection and low-pressure systems,” he said.

The absence of active western disturbances, mainly during the June 10 to June 19 period, was also a reason for the longer dry spell and heatwave prevailing over northwest and central India.

Mohapatra said only three western disturbances, against a normal of four to five, were observed across north India (June 5-10, June 19-25 and June 26-28).

India recorded more than 40,000 suspected heatstroke cases and over 100 heat-related deaths in one of its hottest and longest heatwaves. The intense heat overwhelmed the water supply system and power grids, with Delhi grappling with a severe water crisis.

According to the IMD, around 40 per cent of the country recorded double the number of heatwave days than usual during the April-to-June period. Temperatures breached 50 degrees Celsius in parts of Rajasthan, with night-time temperatures hovering around 35 degrees Celsius at many places.

In Delhi, which logged 40 consecutive days of temperatures of above 40 degrees Celsius since May 13, there have been around 60 heat-related deaths this year, according to media reports.

The IMD had earlier predicted 10 to 20 heatwave days during the summer season against the normal of four to eight days.

In contrast, 20 to 38 heatwave days were recorded in different parts of east, north and central India, including Rajasthan, Madhya Pradesh, Punjab, Haryana, Chandigarh, Delhi, Uttar Pradesh, Himachal Pradesh, Odisha, West Bengal, Jharkhand, Bihar and Gujarat.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

New Delhi/Guwahati:

India recorded more than 40,000 suspected heatstroke cases this summer as a prolonged heatwave killed more than 100 people across the country, while parts of its northeast grappled with floods from heavy rain, authorities said.

Billions across Asia are grappling with extreme heat this summer in a trend scientists say has been worsened by human-driven climate change, with temperatures in north India soaring to almost 50 degrees Celsius (122 degrees Fahrenheit) in one of the longest heatwave spells recorded.

Birds fell from the skies due to extreme heat and hospitals reported an inflow of heat-affected patients as both day and night time temperatures peaked in recent weeks since the start of summer in March.

The health ministry ordered federal and state institutions to ensure “immediate attention” to patients, while hospitals in the capital Delhi, which is also facing a water shortage, were directed make more beds available.

A health ministry official said there were more than 40,000 suspected heatstroke cases and at least 110 confirmed deaths between March 1 and June 18, when northwest and eastern India recorded twice the usual number of heatwave days.

The weather office has forecast above normal temperatures for this month too, as authorities say Indian cities have become “heat traps” due to unbalanced growth.

“During the ongoing heatwave, most bird rescue calls that we receive are due to birds falling from the skies,” said Kartick Satyanarayan, co-founder and CEO of non-profit Wildlife SOS.

“In the past two weeks, Wildlife SOS has been receiving more than 35-40 rescue calls daily, in and around Delhi-National Capital Region. Most of the calls include bird rescue requests.”

Separately, floods and landslides triggered by incessant rain in the northeastern state of Assam killed at least six people on Tuesday night, officials said.

“A landslide buried a woman and her three daughters alive,” a state disaster management official, Siju Das, said by telephone.

“Their house was on a slope, and they died on the spot around midnight,” he said, adding that the bodies were retrieved after a three-hour search operation by rescuers.

“A three-year-old was killed too.”

In Assam, more than 160,000 people were affected, with waters surpassing the danger level in the Kopili, one of the largest tributaries of the Brahmaputra, which ranks among India’s biggest rivers.

More than 30 people in the state have died since the end of May in floods and landslides brought by heavy rain, officials said.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Image used for representative purpose only.
| Photo Credit: RAJESH N

India’s power consumption grew nearly 10% year-on-year to 70.66 billion units (BU) in the first half of April this year, showing improvement in economic activities and consumption patterns, according to the power ministry data.

According to the data, power consumption in the country rose to 70.66 BU during April 1-15 this year from 64.24 MU in the year-ago period.

The peak power demand met or the highest supply in a day rose to about 218 GW in the first half of April compared to 206 GW in the same period a year ago.

The highest supply in a day during the entire month of April last year was about 216 GW.

The ministry has projected a peak power demand of 260 GW during the summer season (April to June) in view of longer heat wave duration. The peak power demand had touched an all-time high of 243 GW in September 2023.

The India Meteorological Department (IMD) has predicted above-normal maximum temperatures in most parts of the country during summer this year.

The experts said that the power demand will increase in the coming days as rains in different parts of the country have reduced the need for cooling appliances like air conditioners, desert coolers etc used during this time of the year.

However, they said that power consumption growth in double digits shows improvement in economic activities and change in consumption patterns.

They are of the view that the consumers in India are also increasing their energy consumption on various appliances and gadgets as is being done in the developed world.

Besides, they pointed out that the increase in electricity in the transport sector like electric buses, cars, rickshaws and railways has also changed the consumption pattern and increased per capita use.

Anthropogenic climate change is turning ambient heat, a relatively banal manifestation of the sun, into an inevitable environmental hazard. In 2023, with the atmospheric carbon dioxide level reaching new heights of 425 ppm, we witnessed the warmest decade on record spanning from 2014 to 2023. Until a few decades ago, hazards of high heat largely existed in confined, fire-based occupational settings or for people who exerted in hot weather for a long time, e.g. soldiers, athletes, and workers, and during occasional heatwaves.

Mentions of heat stroke have been found in literature since ancient times. With rising global temperatures, dangerous high heat has begun permeating our routine indoor spaces. This gradual expansion of the realm of extreme heat is potentially the gravest consequence of climate change for India. 

India has observed a significant mean temperature increase of 0.15 degrees C per decade since 1950, according to a 2020 assessment by the Ministry of Earth Sciences. The observed warming is not occurring evenly across India. Warm days and warm nights have also increased at about seven and three days per decade, respectively, during the period 1951-2015. Currently, 23 States, mainly of plain and coastal regions, are considered more vulnerable to widespread heat impact. However, that doesn’t mean hilly states are safe. Although their maximum temperatures do not reach heatwave threshold levels of 45 degrees C, the population is experiencing higher temperatures compared to previous decades. 

Heat stress and heat stroke

Exposure to severe or continuous heat leads to heat stress. When uncompensated, heat stress manifests as heat-related illnesses. Such illnesses range from superficial/mild and manageable (e.g. prickly heat, heat-related swelling, heat cramps, heat exhaustion) to a medical emergency (i.e. heat stroke). Heat stroke is the most severe of heat-related illnesses: it presents with impaired brain function (i.e. stroke) due to uncontrolled body heating. It is a time-critical condition that often turns fatal if there is a delay or failure in reducing body temperature by  rapid, active  cooling. Besides neurological impairment, high core body temperature (at least 40 degrees C), or hot, dry skin are other heat stroke symptoms. These may be confused with fever. Clinically, a diagnosis of heat stroke poses a unique challenge as it requires the elimination of other causes of stroke, history of infection, and medication overdose.

There are two types of heat stroke. Exertional heat stroke is seen in young, fit individuals performing strenuous physical activities in hot or outdoor environments. It develops within one to two hours of exertion, especially when physical efforts are unmatched by physical fitness, even at moderately high temperatures. On the other hand, relatively slow-developing classic heat stroke is often difficult to fathom, challenging to identify instantly, and deadlier. Observed in individuals lacking the ability to regulate body temperature, e.g. children, the elderly, the sick, and the disabled, this heat stroke is more common during heatwaves. It contributes to about 9-37% of heat-related fatalities during heatwaves, and hence is also called epidemic heat stroke. Importantly, it occurs in hot environments in the absence of strenuous physical activity as individuals fail to perspire or cool off.

Heat stroke is different from other medical conditions in that it does not require the transmission of a virus or bacteria from one person to another, nor does it need the violence of physical trauma that may occur from a gunshot, fall, or due to a cyclone. Someone in perfect health and participating in what seem to be normal activities may die from heat stroke within an hour. 

Pathophysiology of heat

The heat-related illnesses mentioned above are not the only cause of emergency or mortality during hot summer days. Normal human body temperature stays within a narrow range of 36.3-37.3 degrees C. It maintains thermal balance through radiation (40%), evaporation (30%), convection (27%), and conduction (3%). Any external or internal condition that increases body temperature invokes various physiological responses changing cardiovascular, kidney, and metabolic systems, driven by increased blood flow to the skin and dehydration.

A review of the pathophysiology of heat-related illnesses found 27 different pathways that lead to mortality through various combinations of vital organ damage and pathophysiological mechanisms. As such, cardiovascular followed by respiratory, renal, and other chronic causes rank as the most common causes leading to increased emergencies and mortalities during hot days. Hence, estimating the increase in emergency attendance and all-cause deaths during summer has become an easy, practical tool to assess the impact of heat on the population. Cases and deaths that occur solely due to heat stroke represent just the tip of an iceberg.

Heatwaves’ compound effects

Heatwaves are among the deadliest natural hazards. Apart from the aforementioned direct impacts, there are also multiple indirect health impacts due to disruption in services (power, water, transport), increase in food and water-borne diseases, increase in drowning and accidents, and due to overburdened/slowed health services. Globally, thousands of people die yearly and many suffer livelihood consequences due to heat. However, the full impact of a heatwave is often difficult to realise fully until weeks or months later. 

That is not all. Heatwaves also have compound and cascading environmental impacts like concurrent drought, glacial lake outbursts causing flash floods, urban/wildfires, and increased air pollution from ground-level ozone and dust storms. Due to the potential to create widespread health and economic damage, heatwaves can be categorised as a disaster. The disaster risk triad framework delineated in the U.N. Intergovernmental Panel on Climate Change’s Fifth Assessment Reports (2014) can explain its health impacts in that context.

Image: IPCC AR5 risk-centric conceptual framework 

Understanding heat exposure

Multiple physical, socio-economical, environmental, and institutional factors determine health outcomes of heat exposure at the population level. In assessing it, using the disaster risk triad – hazard, exposure, and vulnerability–  concept, the first and foremost challenge comes in estimating the exposure. 

Conventionally, maximum daily temperatures have served the purpose. For example, thresholds for announcing heatwave and severe heatwave warnings for plain areas of India are at maximum temperatures of 45 degrees C and 47 degrees C, respectively. Although the role of high humidity in amplifying heat stress has been recognised, most available heat indices are not adequate for estimating our population’s risk. One widely used heat index (maximum temperature and humidity) equation was formed decades ago, before climate models existed, with assumptions and perceptions of different levels of temperatures among healthy, western individuals. It is also found to be underestimating the severity of heatwaves. The wet bulb globe, which mirrors how the human body cools itself with sweat in outdoor conditions, has been a promising measure. The quest for finding and validating a suitable index for the Indian population is very much on.

Epidemiologically, it is important to note: first, in the current scenario, whichever threshold is used to announce heatwaves, the health impacts of heat on the population do not begin to occur only after those threshold temperature levels are crossed. Health impacts begin much before, even at moderate temperature levels. In terms of external factors, humidity plays a crucial role in creating heat stress by limiting our body’s major cooling mechanism: sweating.

Even at moderate temperatures, like 35 degrees C, if the relative humidity is 70%, it will feel like 50 degrees C to us. In terms of internal factors, heat’s impacts depend on the acclimatisation and build-up of heat stress in the human body. Acclimatisation is a gradual physiological adaptation (short-term) that increases heat tolerance as a person incrementally exerts in a hot setting for a few days. Air conditioning and comorbidities reduce our heat tolerance. Similarly, long-term adaptation occurs in people living in hotter regions over the years. Therefore, tourists from colder regions are particularly at risk of heat stroke when they visit hotter regions.

For example, people living in Ahmedabad might be more adapted to high temperatures than those in Varanasi. In a study of city-level daily mortality, all-cause deaths in Ahmedabad seem to increase after maximum and minimum temperatures crossed 42 degrees C and 28 degrees C, whereas in Varanasi, they increased after 33 degrees C and 27 degrees C. Both physiological adaptations take time to develop. Hence, exposure to sudden extreme temperatures is dangerous for anyone, even healthy and young. The heat-related deaths in Maharashtra in April this year highlighted the dangers of heat. 

Second, not everyone has the same heat exposure at a particular recorded temperature. For example, frail, elderly, living alone, living on the top floor, and not having active cooling were some risk factors associated with heat-related deaths reported during the 1995 Chicago heatwave. Cities retain more heat because of the geometry of built-up building material, concentrated human activities, and lack of vegetation, leading to higher night-time temperatures than the surrounding rural areas. This urban heat island effect contributes to continued heat exposure among city dwellers who, especially, lack sufficient means of active cooling, e.g. fans, air conditioning, and cold drinking water. High night-time temperature has emerged as a significant predictor of heat-related mortality. 

A study conducted in Kolkata in the summer of 2019 found that indoor heat index levels in urban slum dwellings were 5.29 degrees C higher than that outdoors. Dangerously high heat and humidity (at least 45 degrees C) remained for an average of about nine hours/day in urban slum dwellings compared to 2 hours a day in rural houses. These differences were particularly notable at night. During the coolest time of night, the insides of urban dwellings recorded a 6.4 degrees C higher heat index than outdoors, while the insides of rural houses recorded 1.3 degrees C above outdoor levels. Cement walls, clay tiles, corrugated tin roofs, fewer rooms, and crowding made urban slums dangerously hot.

Similarly, a study from Ahmedabad recorded an average 6.7 degrees C higher heat index at the locations where patients with acute heat illnesses were picked up by emergency medical services compared to what was recorded by the nearest weather station during the summer of 2016. At the city level, such differences translate into an increase in all-cause mortality with daily city temperature. Hence, city-level temperature-mortality study has become vital for heat-health action planning.

Children and pregnant women are particularly vulnerable. Higher heat production, greater body surface area, lower sweat production, underdeveloped physiology, lack of risk perception, and poor water replenishment make children, especially infants, more vulnerable to heat impacts. Each 1 degree C temperature increase is associated with reduced birth weight and a 5% increase in the risk of preterm birth and stillbirths. 

Although air conditioning helps, relying on it for our cooling needs only multiplies our existing problems of urban heat islands and global warming. Therefore, the focus should be given to passive cooling inside buildings through better ventilation, window shading, reflective paints, suitable building materials, and traditional methods. At the urban level, understanding heat hotspots, increase in green-blue structures, access to cool spaces, support for suitable adaptation measures, and multisectoral health-centric heat action plans are relevant.

Heating up the puzzle

Because of the multifaceted dimensions of heat impacts, assembling pieces of the population heat exposure puzzle is complicated especially as warming continues. However, understanding existing vulnerabilities and taking action to prevent extreme heat’s impact is very much in our hands. And importantly, heat-related illnesses are preventable. Assessing patterns of socio-economic, demographic, and environmental factors, access to basic services, disease distribution, existing institutional mechanisms, and preparedness helps to take stock of the situation and to prioritise resource allocation for vulnerable populations, and strengthen institutional responses. 

Governance, health workforce, vulnerability and adaptation assessment, integrated risk monitoring and early warning, climate-resilient and sustainable technologies and infrastructure, management of environmental determinants of health, and climate-informed health programmes are some of the components for building climate-resilient health systems, according to the World Health Organisation.

Public health action

Adaptation measures to extreme heat are essential and urgent as our actions in this decade have the potential to change the course of irreversible planetary consequences. The window for action is closing fast. Because emitted greenhouse gases (GHG) will continue global warming until carbon levels are settled, even after net zero may be achieved, a health-centric adaptation focus should be seriously followed in every sector. This will also help us stay on course for the Sustainable Development Goals. 

In the health sector, the National Programme on Climate Change and Human Health (NPCCHH), a health programme of the Ministry of Health and Family Welfare, technically supported by the National Centre for Disease Control, works to achieve goals envisioned in the ‘Mission on Health’ under the Prime Minister’s Climate Council. Since its launch in 2019, the programme is carrying out its mandate to increase general awareness, build the capacity of health professionals and strengthen the health sector to respond to changing disease patterns and to withstand increasing extreme weather events in the context of climate change.

Many of these measures reach communities and health facilities across the country through an organisational structure under NPCCHH that includes nodal officers in states and districts in health departments and the army of medical officers and community health workers. It is trying to address multiple climate-sensitive health issues with a priority focus on the health impacts of heat, other extreme weather events, air pollution; vector-borne and water-related illnesses in the context of climate change; and green and climate-resilient health facility infrastructure. 

Extensive awareness efforts, cascading training of health professionals, early warning dissemination, and integrated health surveillance are the key activities being carried out under the programme. The programme launched the National Action Plan on Heat-Related Illnesses in July 2021. Advisories for the general public (including “do’s and don’ts”) and for state health departments for health sector preparedness are issued through the health ministry at the beginning of the summer every year. National heat-related illness surveillance focuses on heat stroke, emergency admissions, and cardiovascular and all-cause mortalities as reported by health facilities. 

Globally, the health sector contributes to about 5.2% of the carbon footprint, and India’s health sector is the seventh largest contributor. So apart from various adaptation measures, efforts are also directed towards reducing GHG emissions from the health sector, under the NPCCHH, through measures like energy efficiency, renewable energy transition, passive cooling like cool/green roofs, water conservation, and rainwater harvesting, among others. After all, mitigation is the panacea for climate change. 

India is highly vulnerable to climate change impacts. It is the third largest emitter of GHG currently. At the current global warming of 1.2 degrees C, frequent, intense, and expansive heatwaves are no longer a prediction. They are becoming a painful reality.  According to a recent assessment, the April 2023 heatwave in India was made 30-times more likely by climate change. With the El Nino settling in, the coming years might witness record-breaking summers. It will only worsen if we collectively fail to control GHG and knowingly slide towards the inevitable 1.5 degrees C mark. Without an immediate reduction in fossil-fuel-based energy which powers our buildings, vehicles, agriculture, supply chains, and many basic services, we will be ensuring future global warming and its wider impacts on our health and life of future generations. Let’s pledge to reduce our impacts on the environment. 

Our every action counts!

Dr. Purvi Patel is a public health specialist with experience working in the area of climate change, heat and health.