India declares a heat wave whenever temperatures are above 40 degrees Celsius (113 degrees Fahrenheit) in the plains and 30 degrees Celsius (86 degrees Fahrenheit) or more in its hilly regions.
In recent weeks, parts of the capital reported temperatures up to 51 C (123.8 F), triggering record demand for electricity and leading to frequent power cuts in the city, which is also battling a severe water crisis.