Context

Recently, the Indian Meteorological Department (IMD) issued a red alert for heatwaves in Delhi, Punjab, Haryana, and most parts of Western Rajasthan.

IMD Issues Severe Heatwave Red Alert for Punjab Haryana and Chandigarh

• The Chandigarh administration is reportedly considering shutting down schools by noon, given these conditions.
• A US-based group of climate scientists called ‘Climate Central’ said human-caused climate change has made this intense heat much more likely. 

Enroll now for UPSC Online Course

About Heatwave Red Alert 

• Refers: A red alert refers to an extreme heat warning. 
• Time Persistence: It means that a severe heatwave has persisted for more than two days or the total number of heat/severe heatwave days has been more than six days.
• Concerns: 
  • According to IMD, there is a very high likelihood of developing heat illness and heat stroke in all ages. 
  • Extreme care needs to be exercised for vulnerable people, such as the elderly, infants and those with chronic diseases. 
  • According to the World Health Organization, more than 1,66,000 people died as a result of heatwaves between 1998 and 2017.

About Heatwave

• Refers: For every region, a heatwave is determined based on the degree of difference from its usual temperatures. 
  • • 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. 
    • For coastal areas, it is when the maximum temperature departure is 37°C or more than normal.
  • Such temperatures must be recorded at least in two stations in a meteorological sub-division for at least two consecutive days. The heatwave is declared on the second day.
• Affected Regions of India: Heatwaves cover Punjab, Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand, West Bengal, Odisha, Madhya Pradesh, Rajasthan, Gujarat, parts of Maharashtra and Karnataka, Andhra Pradesh and Telangana. 
  • Sometimes they occur in Tamil Nadu and Kerala, too. 
  • Maximum temperatures above 45°C are observed mainly in Rajasthan and the Vidarbha region in May.

Severe Heatwave

If the prevalent temperature is 4.5°C to 6.4°C more than normal, it is classified as a heatwave. A rise of more than 6.4°C is considered a severe heatwave. May is the peak month for heatwaves in India.

About Heatwave Alert

• Classification: 
  • On the Qualitative Basis: According to the IMD’s website, Qualitatively, heat wave is a condition of air temperature which becomes fatal to the human body when exposed. 
  • On the Quantitative Basis: Quantitatively, it is defined based on the temperature thresholds over a region in terms of actual temperature or its departure from normal.

Enroll now for UPSC Online Classes

DOWNLOAD PDF