A punishing heat wave battered parts of Delhi with seven of the 22 weather stations in the national capital recording maximum temperatures above the 45-degree-Celsius mark. The sweltering conditions saw the peak power demand in Delhi soar to 6,916 MW on Tuesday, the highest so far this season, officials said.?

The city had recorded a peak power demand of 7,695 MW last summer and this year it might reach 8,100 MW, they said. Dust-raising winds gusting up to speeds of 48 kilometres per hour and an overcast sky brought slight relief from the blistering heat in the evening. Generally cloudy weather, thunderstorm and light rain are expected on Wednesday afternoon or evening.

The maximum temperature at a few places, including Najafgarh (46.7 degrees Celsius), breached the 46-degree mark for the second consecutive day on Tuesday. The Safdarjung Observatory, Delhi's primary weather station, recorded a maximum temperature of 43.5 degrees Celsius -- three notches above normal.

The mercury soared to 45.1 degrees Celsius at Ridge in central Delhi, 45.2 degrees at Jafarpur, 45.2 degrees at Narela, 46.1 degrees at Pitampura, 45.7 degrees at Pusa and 46.2 degrees at Sports Complex.

The threshold for a heat wave is met when the maximum temperature of a 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 a minimum 4.5 degrees.

The India Meteorological Department said a western disturbance active over the western Himalayan region will bring rain, hailstorm and gusty winds in the northwestern plains on Wednesday. As a result, the maximum temperature will drop to 36 degrees Celsius by Thursday, it said.

Earlier this month, the weather office had predicted below-normal maximum temperatures and fewer heatwave days in northwest India in May. With the India Meteorological Department anticipating a slight delay in the arrival of the southwest monsoon, the maximum temperatures are likely to remain above normal for a longer-than-usual period.

Heat waves in India are becoming more frequent and severe due to climate change, with over 90 per cent of the country in the "extremely cautious" category or "danger zone" of their impacts, according to a study conducted at the University of Cambridge.?The study also revealed that Delhi is particularly vulnerable to severe heatwave impacts despite its recent state action plan for climate change failing to reflect this fact.