Heat Action Plan (HAP)

Heat Action Plan (HAP)


As temperatures rise across India, the onset of heatwaves has become increasingly frequent, posing significant challenges to public health and infrastructure.

  • The India Meteorological Department (IMD) has already issued heat alerts in several regions, indicating the early arrival of extreme heat conditions.


GS-01 GS-03 (Geophysical Phenomena, Climate Change)

Heat Wave:

  • A heatwave is defined by the IMD based on maximum temperature thresholds specific to different regions. In the plains, a heatwave is declared if the maximum temperature exceeds 40 degrees Celsius, while in coastal areas and hills, the threshold is 37 degrees Celsius and 30 degrees Celsius, respectively.
  • It is also described as extreme heat.
  • They denote long lasting periods of extremely hot weather, posing adverse effects on human health, the environment, and the economy.
  • India is especially susceptible to heat waves considering its tropical climate, which have escalated in frequency and intensity in recent times.
  • The severity of a heatwave is determined by the departure of temperature from normal conditions, categorized as ‘normal’ or ‘severe’ based on predefined ranges or actual maximum temperature thresholds.
    • Heat Wave: Deviation from normal temperature ranges from 4.5°C to 6.4°C.
    • Severe Heat Wave: Deviation from normal temperature exceeds 6.4°C.
    • Severe Heat Wave: Occurs when the actual maximum temperature equals or surpasses 47°C.

India Meteorological Department:

  • It was established in 1875.
  • It works as an agency of the Ministry of Earth Sciences of the Government of India.
  • It is headquartered in New Delhi.
  • The Indian Meteorological Department (IMD) categorizes a heat wave if the maximum temperature of a region reaches 40°C or higher for plains and 30°C or higher for hilly areas.

Consequences of heatwaves:

  • Heatwaves pose serious risks to public health, with heat-related illnesses such as heatstroke, dehydration, and heat exhaustion becoming more prevalent.
  • Vulnerable populations, including the elderly, children, and outdoor workers, are particularly susceptible to these health hazards.
  • It can lead to economic losses due to decreased productivity, damage to infrastructure, and increased healthcare expenditures.

How are heatwaves formed and processed?

  • Heatwaves typically occur when high-pressure systems trap warm air near the Earth’s surface, leading to prolonged periods of elevated temperatures.
  • Urban areas are particularly vulnerable to heatwaves due to the urban heat island effect, where concrete and asphalt surfaces absorb and retain heat, further exacerbating temperatures.
  • The intensity and duration of heatwaves are influenced by factors such as humidity, wind patterns, and geographical features.

Measures to address heatwaves:

  • Governments at various levels have developed Heat Action Plans (HAPs) to mitigate the adverse impacts of heatwaves and enhance preparedness. These plans include a range of strategies and interventions aimed at preventing heat-related illnesses, protecting vulnerable populations, and minimizing economic losses. Key measures recommended by HAPs include:
    • Early warning systems: Using forecasts to alert the public and relevant authorities about impending heatwaves.
    • Public awareness campaigns: Educating the public about the risks associated with heatwaves and promoting preventive measures.
    • Establishment of cooling centers and heat shelters: Providing refuge for individuals during periods of extreme heat.
    • Provision of clean drinking water: Ensuring access to safe drinking water to prevent dehydration.
    • Healthcare preparedness: Equipping hospitals with necessary supplies and trained personnel to manage heat-related illnesses.
    • Long-term strategies: Implementing urban planning measures such as tree planting, cool roofing technologies, and green spaces to reduce urban heat island effects and enhance resilience to heatwaves.