Why in News?

A recent study by the Council on Energy, Environment and Water (CEEW), titled ‘How Extreme Heat is Impacting India’, reveals that 57% of Indian districts, home to 76% of the population, face high or very high risk from extreme heat.

States facing the highest risk include Delhi, Maharashtra, Goa, Kerala, Gujarat, Rajasthan, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, and Uttar Pradesh.

CEEW, based in New Delhi, is one of the world’s leading and best-managed independent climate think tanks.

What’s in Today’s Article?

• Understanding Heat Risk: Not the Same as Heatwaves or Heat Stress
• Key Factors Driving Heat Risk in India
• Key Findings of The Study

Understanding Heat Risk: Not the Same as Heatwaves or Heat Stress

• Heatwaves
  • While they do not have a universal definition, heatwaves are essentially prolonged periods of abnormally high temperatures in a specific region.
• Heat Stress
  • Occurs when the body temperature exceeds 37°C.
  • Body struggles to release excess heat, causing discomfort, cramps, and exhaustion.
  • If body temperature exceeds 40°C, it may lead to heat stroke.
• Heat Risk
  • According to the CEEW study, heat risk refers to the probability of heat-related illness or death due to extreme temperatures.
  • It is determined by three key factors:
    • Intensity of heat and compounding effects (e.g., humidity),
    • Degree of exposure, and
    • Vulnerability of affected communities (e.g., age, health conditions).

Key Factors Driving Heat Risk in India

• Rise in Very Warm Nights
  • Between 2012 and 2022, over 70% of Indian districts experienced five or more additional very warm nights each summer.
  • Warm nights prevent the body from cooling down after hot days, increasing the risk of heat strokes and worsening non-communicable diseases like diabetes and hypertension.
• Increase in Relative Humidity in North India
  • Relative humidity in the Indo-Gangetic Plain rose from 30–40% (1982–2011) to 40–50% (2012–2022).
  • High humidity hampers cooling through sweat, intensifying heat stress, especially when body temperature exceeds 37°C.
• Urbanisation and Population Density
  • Cities like Mumbai and Delhi face higher exposure due to dense populations.
  • Rapid urbanisation in tier II and III cities has led to increased night-time heat due to heat-absorbing concrete infrastructure.
• Socio-Economic and Health Vulnerabilities
  • Districts in Andhra Pradesh, Maharashtra, Haryana, Punjab, Chhattisgarh, Bihar, and Uttar Pradesh are particularly vulnerable.
  • Factors include a high share of elderly populations and prevalence of chronic health conditions (e.g., diabetes, hypertension).

Key Findings of The Study

• 2024: Warmest Year on Record
  • 2024 marked the hottest year globally, including in India.
  • Global average temperature was 1.5°C above pre-industrial levels (1850–1900).
  • India’s temperature was 1.2°C higher than the 1901–1910 average.
• India’s Climate Impact: Already Evident
  • India experienced its longest recorded heatwave since 2010 & over 44,000 cases of heatstroke were reported in 2024 alone.
• Inadequate Heat Action Plans (HAPs)
  • India’s HAPs (early warning and preparedness plans) are often:
    • Lacking long-term strategies, or
    • Poorly implemented, even when they exist.
  • According to the Sustainable Futures Collaborative (SFC), this weakens India’s response to growing heat threats.
• Future Risks
  • Without stronger planning and execution, heat-related deaths may rise.
  • The country faces increasing threats from more frequent, intense, and prolonged heatwaves.