India is facing one of the longest and most severe summers, 14 of 36 subdivisions in the country have recorded over 15 heat wave days between March 1 to June 9, data compiled by the India Meteorological Department (IMD), has shown.

Only the northeastern states, coastal Karnataka and parts of Marathwada have been spared from heat wave conditions during this period as per subdivision-wise data with IMD. The highest heat wave days have been recorded over Odisha (27) followed by Rajasthan (23), Gangetic West Bengal (21), Haryana (20), Chandigarh (20), Delhi (20) and West Uttar Pradesh (20).

Even high-altitude areas have not been spared from heat waves with Jammu and Kashmir observing six days of heat wave, Himachal Pradesh (12), Uttarakhand (2). Coastal areas such as Kerala and Tamil Nadu have recorded five and fourteen heat wave days, respectively.

Moreover, the IMD has warned of severe heatwave conditions over northern parts of India at least for the next four to five.

Climate scientists are taken aback by the scale and expanse of extreme heat this year.

A heat wave is declared when the maximum is over 40 degrees C over the plains, over 37 degrees C over coastal areas, and over 30 degrees C o in the hills with the deviation from normal between 4.5 and 6.4 degrees C above the average maximum. If these conditions persist for two consecutive days, a heat wave is declared on the second day. A severe heat wave is declared when the deviation is more than 6.4 degrees C above normal.