Intense heat sweeps large swathes of India, maximum temperatures settle four to six degrees higher

​The threshold for a heat wave is met when the maximum temperature of a weather station reaches at least 40 degrees Celsius in the plains, 37 degrees in the coastal areas and 30 degrees in the hilly regions, and the departure from normal is at least 4.5 notches. A severe heat wave is declared if the departure from normal temperature exceeds 6.4 notches.
Source – ETHealth World