The average heat index in India is increasing significantly per decade at the rate of 0.56°C and 0.32°C in summer and monsoon respectively.
This is as per a recent research by India Meteorological Department and Indian Institute of Tropical Meteorology.
Heat index is a measure of the stress placed on humans by increased levels of temperature and moisture.
The higher the heat index, the hotter the weather one feels, since sweat does not readily evaporate and cools the skin.
Of 25 mega cities analysed, 17, including Mumbai, Pune, Kolkata and Ahmedabad, have long-term average summer heat index in 'very hot category'.
The study found that Mumbai and Pune from west India are in the 'hot category' of the index in monsoon.
Most mega cities in north India, including Delhi and Amritsar, are in hot category of the heat index during the summer season and in 'very hot category' in monsoon.
'Very hot' category is considered dangerous, with health effects such as heat cramps, exhaustion and heatstroke with prolonged exposure or physical activity.
The 'hot category' requires people exposed to it to take extreme caution. The study found that 10 mega cities show significant increasing trends in monsoon heat index, including Mumbai and New Delhi.
The stilling of winds is an interesting phenomenon taking place, even as Indian megacities become unlivable.
The study used monthly average maximum temperature and relative humidity records to analyse heat index during summer and monsoon from 1951 to 2010 for 60 years.
Indian Institute of Tropical Meteorology- The Indian Institute of Tropical Meteorology or IITM is a scientific institution based in India for expanding research in meteorology of the tropics.
- Addressing this in general with special reference to monsoon meteorology of India, IITM is based in Pune.
- Address: Dr. Homi Bhabha Road, Pashan, Panchawati, Pune, Maharashtra 411008
- Founded: 1962
