Avoiding Adverse Impacts of Heat Waves in India

M. Bhaskara Rao
Abhinav Walia

Prof. M. Bhaskara Rao is a Senior Consultant of Disaster Management at Puducherry Disaster Management Authority (PDMA), Puducherry

Abhinav Walia is a Ph.D. scholar at The University of Newcastle, Australia, and has a decade-long national and international work experience as a Disaster Management professional.

In India, over the years heat waves have become fatally catastrophic and resulting in a large number of human and animal mortalities. Climate Change is driving temperatures higher as well as increasing the frequency and severity of heat waves in India. As heat waves are becoming more intense and frequent across India, there is an imminent need to take continuous efforts to mitigate the adverse impacts of heat waves. This paper briefly describes the various mechanisms and approaches to address heat wave related threats, relief and response measures to be taken as well as long-term heat risk reduction strategies.

A Heat Wave is a period of excessively hot weather, which may be accompanied by high humidity.  A heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heatwave in a cooler area if they are outside the normal climate pattern for that area. The term “Heat Wave” is applied to hot weather variations and to extraordinary spells of heat which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather that can be a natural disaster and a danger because heat and sunlight may overheat the human body. Heat waves can usually be detected using forecasting instruments so that a warning call can be issued.

Qualitatively, the heat wave is a condition of air temperature which becomes fatal to the human body when exposed. Quantitatively, it is defined based on the temperature thresholds over a region in terms of actual temperature or its departure from normal. In certain countries, it is defined in terms of the heat index based on temperature and humidity or based on the extreme percentile of the temperatures. In India, over the years, heat waves have become fatally catastrophic and resulting in a large number of human and animal mortalities. Climate Change is driving temperatures higher as well as increasing the frequency and severity of heat waves in India. In the past few years, India is experiencing the impact of climate change in terms of increased instances of heat wave every year. According to the special report released by the Inter-governmental Panel on Climate Change (IPCC, October 2018), global warming of l.5°C-2°C will worsen the situation along with unavoidable poverty and health risks that come with global warming. Environmental degradation, increase in pollution, unnecessary, uncontrolled, and excess use of plastic, Deforestation and increasing constructed area in India are also adding to environmental instability and increasingly contributing to global warming and climate change.

In India, many States such as Andhra Pradesh, Telangana, Odisha, Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh, Maharashtra, Karnataka, Bihar, Jharkhand, West Bengal, Haryana, Punjab, and Delhi are affected during the heat wave season. Sometimes it occurs in Tamil Nadu & Kerala also. Heat waves adversely affect human and animal lives. However, maximum temperatures of more than 45°C were observed mainly over Rajasthan and Vidarbha region in the month of May. Accurate and relevant information regarding heat wave casualties is challenging. In most parts of India, the actual numbers of deaths resulting from heat waves are higher than the reported numbers. Mostly the deaths in rural areas due to heat waves are often not reported/collected. As heat waves are becoming more intense and frequent across the country, we should take continuous efforts towards devising strategies to mitigate the adverse impacts of heat waves, particularly on the poor and disadvantaged sections of society. We also need to continuously upgrade our mechanisms to address heat-related threats, relief and response measures as well as long-term heat risk reduction strategies.

Criterion for declaring Heat Wave

A heat wave is considered if the maximum temperature of a station reaches at least 40°C or more for Plains and at least 30°C or more for Hilly regions.

a) Based on Departure from Normal Heat Wave: Departure from normal is 4.50°C to 6.40°C Severe Heat Wave: Departure from normal is >6.40degree C.

b) Based on Actual Maximum Temperature Heat Wave: When actual maximum temperature ≥ 4.50°C Severe Heat Wave: When actual maximum temperature ≥47 degree C.

c) If the above criteria are met at least in 2 stations in a Meteorological sub-division for at least two consecutive days and it is declared on the second day.

Criterion for describing Heat Waves for coastal stations in India

When the maximum temperature departure is 4.50°C or more from normal, a Heat Wave may be described provided the actual maximum temperature is 37°C or more. The peak month of the heat waves over India in May.

Warm Night: It is considered only when the maximum temperature remains 40 degree C or more. It is defined based on departures or actual minimum temperatures as follows:

Warm night: minimum temperature departure is 4.50 degree C to 6.40 degree C

Very warm night: minimum temperature departure is >6.40 degree C

India Meteorological Department (IMD) has a big network of surface observatories covering the entire country to measure various metrological parameters like Temperature, Relative humidity, pressure, wind speed & direction, etc. Based on daily maximum temperature station data, climatology of maximum temperature is prepared to find out the normal maximum temperature of the day for a particular station. Thereafter, IMD declares a heat wave over the region as per its definition. IMD issues temperature forecasts & warnings in the following range:

a) Short to medium range (lead time/validity of 1 to 5 days)

b) Extended range (lead time/validity up to 4 weeks)

c) Seasonal range (lead time/validity up to 3 months)

IMD issues location, District, Meteorological Sub-division, and Homogeneous regions temperature forecasts to its various users and keeps on its IMD Website (https://mausam.imd.gov.in/). A common man may get heat wave information from, the All India Weather Forecast Bulletin (https://mausam.imd.gov.in/imd_latest/contents) and special heat wave guidance bulletins (http://internal.imd.gov.in/pages/heatwave) during 1 April to 30 June every day. The heat wave information is shared with concerned State Disaster Management Authorities, Government Authorities, Media, and other stakeholders like Indian Railway, Health departments, Power Sector, etc. The general public is also informed through Print & Electronics Media.

Heat Waves and Health

The scale and nature of the health impacts of heat depend on the timing, intensity, and duration of a temperature event, the level of acclimatization, and the adaptability of the local population, infrastructure, and institutions to the prevailing climate. The precise threshold at which temperature represents a hazardous condition varies by region, other factors such as humidity and wind, local levels of human acclimatization, and preparedness for heat conditions. The negative health impacts of heat are predictable and largely preventable with specific public health actions. Exposure to excessive heat has wide-ranging physiological impacts on all humans, often amplifying existing conditions and resulting in premature death and disability.

Some key health impacts of the heat wave

  • Rapid rises in heat gain due to exposure to hotter than average conditions compromise the body’s ability to regulate temperature and can result in a cascade of illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia.
  • Deaths and hospitalizations from excessive heat can occur extremely rapidly (same day), or have a lagged effect (several days later) and result in accelerating death or illness in the already frail, particularly observed in the first days of heat waves. Even small differences from seasonal average temperatures are associated with increased illness and death. Temperature extremes can also worsen chronic conditions, including cardiovascular, respiratory diseases and diabetes-related conditions.
  • Heat also has important indirect health effects. Heat conditions can alter human behavior, the transmission of diseases, health service delivery, air quality, and critical social infrastructures such as energy, transport, and water.

Psychological and Sociological effects of Heat Wave

In addition to physical stress, excessive heat causes psychological stress, to a degree that affects performance, and is also associated with an increase in violent crime. High temperatures are associated with increased conflict both at the interpersonal level and at the societal level. In every society, crime rates go up when temperatures go up, particularly violent crimes such as assault, murder, and rape. Furthermore, in politically unstable countries, high temperatures are an aggravating factor that led to civil wars. Additionally, high temperatures have a significant effect on income. A study of counties in the United States found that the economic productivity of individual days declines by about 1.7% for each degree Celsius above 15 °C (59 °F).

Heat waves can cause roads and highways to buckle and melt, water lines to burst, and power transformers to detonate, causing fires. Heatwaves can also damage railroads, such as buckling and kinking rails, which can lead to slower traffic, delays, and even cancellations of service when rails are too dangerous to traverse by trains.

Heat waves often lead to electricity spikes due to increased air conditioning use, which can create power outages, exacerbating the problem. During the 2006 North American heat wave, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformers failed, leaving thousands without power for as long as five days. The 2009 South Eastern Australia Heat Wave caused the city of Melbourne, Australia to experience some major power disruptions which left over half a million people without power as the heat wave blew transformers and overloaded a power grid.

IMD issues special heat wave warning guidance bulletins (at 0800 & 1600 hours IST) at meteorological sub-division & district levels to different users like the Ministry of Home Affairs, National Disaster Management Authority, State Disaster Management Authority, Deputy Commissioner/District Magistrates of different districts of states, health department, Indian Railway, Road transport, Media, etc. IMD conducts the preseason exercise at the state & national levels. IMD also contributes to the preparation of heat wave guidelines and heat action plans. IMD provides the required past data for heat wave advisories and development.

Favourable conditions for Heat Waves

a. Transportation / Prevalence of hot dry air over a region (There should be a region of warm dry air and an appropriate flow pattern for transporting hot air over the region).

b. Absence of moisture in the upper atmosphere (As the presence of moisture restricts the temperature rise).

c. The sky should be practically cloudless (To allow maximum insulation over the region).

d. Large amplitude anti-cyclonic flow over the area.

Heat waves generally develop over Northwest India and spread gradually eastwards & southwards but not westwards (since the prevailing winds during the season are westerly to north-westerly). But on some occasions, heat waves may also develop over any region in situ under favourable conditions.

How heat discomfort is determined?

Heat discomfort is determined by a combination of meteorological (temperature, Relative Humidity, wind, direct sunshine), social/cultural (clothing, occupation, accommodation), and physiological (health, fitness, age, level of acclimatization etc.) factors.

Heat Index

The heat index is the combination of air temperature and relative humidity. It is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. Heat is tolerable for the general public but moderate health concern for vulnerable people e.g. infants, the elderly, and people with chronic diseases. Extreme care is needed for vulnerable people. The following measures should be taken:

(a)          Avoid heat exposure.

(b)          Wear lightweight, light-coloured, loose, cotton clothes.

(c)           Cover your head (with a cloth, hat, or umbrella)

(d)          Avoid dehydration.

(e)          Drink sufficient water- even if not thirsty.

(f)           Use ORS, homemade drinks such as Lassi, Torani (rice water), Lemon Water, Buttermilk, etc.

Symptoms

Symptoms of Sunburn and its First Aid

  • Symptoms: Skin redness and pain, possible swelling, blisters, fever, and headaches.
  • First Aid: Take a shower, using soap, to remove oils that may block pores preventing the body from cooling naturally. If blisters occur, apply dry, sterile dressings and get medical attention.

Symptoms of Heat Cramps and its First Aid

  • Symptoms: Painful spasms usually in the leg and abdominal muscles or extremities. Heavy sweating.
  • First Aid: Move to a cool or shaded place. Apply firm pressure on cramping muscles or gentle massage to relieve spasms. Give sips of water. If nausea occurs, discontinue.

Symptoms of Heat Exhaustion and its First Aid

  • Symptoms: Heavy sweating, weakness, skin cold, pale, headache, and clammy. Weak pulse. Normal temperature is possible. Fainting, vomiting.
  • First Aid: Get the victim to lie down in a cool place. Loosen clothing. Apply cool, wet cloth. Fan or move victim to an air-conditioned place. Give sips of water slowly and if nausea occurs, discontinue. If vomiting occurs, seek immediate medical attention. Or call 108 and 102 for Ambulance.

Symptoms of Heat Stroke (Sun Stroke) and its First Aid

  • Symptoms: High body temperature (106+F). Hot, dry skin. Rapid, strong pulse. Possible unconsciousness. The victim will likely not sweat.
  • First Aid: Heat stroke is a severe medical emergency. Call 108 and 102 for an Ambulance for emergency medical services or take the victim to a hospital immediately. Delay can be fatal. Move victim to a cooler environment. Try a cool bath or sponging to reduce body temperature. Use extreme caution. Remove clothing. Use fans and/or air conditioners. DO NOT GIVE FLUIDS.

Health Impacts of Heat Waves

The health impacts of Heat Waves typically involve dehydration, heat cramps, heat exhaustion, and/or heat stroke. The signs and symptoms are as follows:

  • Heat Cramps: Edema (swelling) and Syncope (Fainting) generally accompanied by fever below 39*C i.e.102*F.
  • Heat Exhaustion: Fatigue, weakness, dizziness, headache, nausea, vomiting, muscle cramps, and sweating.
  • Heat Stoke: Body temperatures of 40*C i.e. 104*F or more along with delirium, seizures, or coma. This is a potentially fatal condition (source: https://ndma.gov.in/en/2013-05-03-08-06-02/disaster/natural-disaster/heat)

Measures to minimize the impact during the heat wave

  • Avoid going out in the sun, especially between 12.00 noon and 3.00 p.m.
  • Drink sufficient water and as often as possible, even if not thirsty
  • Wear lightweight, light-coloured, loose, and porous cotton clothes. Use protective goggles, umbrella/hat, shoes/ chappals while going out in sun.
  • Avoid strenuous activities when the outside temperature is high. Avoid working outside between 12 noon and 3 p.m.
  • While travelling, carry water.
  • Avoid alcohol, tea, coffee, and carbonated soft drinks, which dehydrate the body.
  • Avoid high-protein food and do not eat stale food.
  • If you work outside, use a hat or an umbrella and also use a damp cloth on your head, neck, face, and limbs
  • Do not leave children or pets in parked vehicles
  • If you feel faint or ill, see a doctor immediately.
  • Use ORS, homemade drinks like Lassi, Torani (rice water), lemon water, buttermilk, etc. which helps to re-hydrate the body.
  • Keep animals in shade and give them plenty of water to drink.
  • Keep your home cool, use curtains, shutters or sunshade and open windows at night.
  • Use fans, damp clothing and take bath in cold water frequently. (source: https://ndma.gov.in/en/heat-do-s-and-dont-s.html)

Heat Wave Prevention, Preparedness, and Mitigation Measures

  • Preparation/Revision of Heat Wave Action Plan
  • Real-time surveillance and evaluation of weather situation
  • Disseminate the information received from the India Meteorological Department (IMD) to the public at large
  • Putting up display boards for color-coded heatwave alerts and Do’s and Don’ts in public places such as parks, hospitals, etc.
  • Multiple mediums of communication (preferably in local languages) like TV, Radio, and newspaper for awareness.
  • Identify and reduce the awareness gap through disseminating information using pamphlets, hoardings, and LED displays on advertisement boards.
  • Change in timings of schools, colleges, offices, markets, etc.
  • Prepare Standard Operations Procedures (SOP) for heat wave response
  • Provide funds for Heat Wave Mitigation and develop monitoring mechanism for implementation of Heat Wave Action Plan and issue necessary directions/instructions
  • Installing temporary kiosks for shelter, and distribution of water, medicines, etc.
  • Developing mobile applications for spreading awareness on heat-related issues and locating shelters, drinking water kiosks, etc.
  • Issuing advisories for tourists.
  • Providing shade and drinking water for on-duty traffic personnel.
  • Setting up special cool shelters for “Wage Employment programs” such as Mahatma Gandhi National Rural Employment Guarantee Scheme (MGNaREGA).
  • Ensure LED Display boards are installed at strategic locations displaying real-time weather data pertaining to Rainfall, Temperature, Humidity, and Wind Speed and precautionary measures needed to be taken.
  • Involve Environment, Science and Technology, and Forest departments for collating local coping and adaptation strategies, indigenous technologies such as vernacular building materials, construction of the green buildings, Energy Conservation Building Code (ECBC), etc. related to heat wave risk mitigation.
  • Identify “heat hot-spots” in India through appropriate tracking and modeling of meteorological data, and promote the timely development and implementation of local Heat Action Plans with strategic inter-agency coordination and a response that targets the most vulnerable groups.
  • Heat wave mitigation management should be added to the school curriculum to sensitize school children and local people. Training programs on heat wave awareness should be conducted.
  • A national-level strategy and plan to combat heat waves should be developed.

Heat Wave Do’s and Don’ts

Do’s:

  • Try to stay in cold places.
  • Use an umbrella during hot days.
  • Wear thin loose cotton garments, preferably of white colour.
  • Wear a hat of cotton or a turban
  • Avoid outdoor physical activity from 12 to 3 p.m. if unavoidable attend to only light physical activity under the hot sun.
  • Take ample water along with salted butter milk or glucose water.
  • Take measures to reduce the room temperature like watering, using window shades, fanning and cross ventilation
  • Shift the person with heat stroke symptoms to a cool dwelling.
  • The person suffering with heat stroke should have minimum clothing.
  • The person suffering with heat stroke has to be sponged with cold water, indirect application of ice packs.
  • The person suffering with heat stroke should be kept in between ice blocks
  • If the persons affected with heat stroke and are not showing any improvement, he/she should be shifted to a hospital immediately, preferably with cooling facility.

Don’ts:

  • Do not expose to direct sun light or hot breeze.
  • Do not move under hot sun without umbrella cap or turban.
  • Do not use black and synthetic, thick clothes during summer season.
  • Do not leave children or pets in parked vehicles.
  • Do not attend to strenuous physical activity under the hot sun.
  • Do not allow direct hot air into the living rooms
  • Do not drink alcohol, tea, coffee, and carbonated soft drinks, which dehydrate the body and avoid high-protein food and do not eat stale food
  • Do not delay in shifting the person suffering with heat stroke to a cool place.
  • Do not allow the person suffering with heat stroke to have thick and tight clothing.
  • Do not allow the person suffering with heat stroke to be sponged with hot water and to be exposed to hot air.
  • Do not delay in shifting the person affected with heat stroke whenever there is no improvement in his condition

Conclusion

In India, over the years, heat waves have become fatally catastrophic. Unplanned urban growth and development, changes in land use and land cover, densely populated areas and increasing urban sprawl are exacerbating the impact of heat waves. We need to continuously upgrade our mechanisms to address emerging heat-related threats, reflect best practices and draw lessons from past experiences. A comprehensive heat preparedness and response requires involvement from government authorities, non-governmental organizations research, scientific and technological institutes and civil society organizations. Our continuous efforts to mitigate the adverse impacts of heat waves, particularly upon the poor and disadvantaged sections of the society should be directed towards devising and improving strategies to improve inter-agency coordination and ensure information & knowledge dissemination. With a vibrant disaster management mechanism in place in India, with the governments measures to reduce pollution and environmental degradation, climate change adaptation and mitigation measures and with involvement and coordination among various ministries/ departments, state governments, organizations institutions, individuals and communities, it is quite possible to mitigate the adverse impacts of heat waves and protect lives and preventing illnesses and ensure a safe and disaster resilient India.

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