The national capital reeled under a scorching heatwave on Wednesday with the mercury settling six notches above normal in most areas, the weather department said.
The Palam Observatory recorded the highest maximum temperature at 47.2 degrees Celsius, slightly less than Tuesday (47.6 degrees Celsius).
The Safdarjung Observatory, which provides representative figures for the city, recorded a maximum of 45.9 degrees Celsius.
On Tuesday, it had recorded a high of 46 degrees Celsius.
The last time the mercury touched the 46-degree mark at the Safdarjung weather station was on May 19, 2002, said Kuldeep Srivastava, the head of the regional forecasting center of the India Meteorological Department (IMD).
The all-time record for Safdarjung in May is 47.2 degrees Celsius. It was recorded on May 29, 1944.
The IMD said the weather stations at Lodhi Road and Ayanagar recorded maximum temperatures of 45.1 degrees Celsius and 46.7 degrees Celsius respectively.
Mr Srivastava said some respite from the stifling heat is expected on May 28 due to a fresh Western Disturbance and easterly winds at lower levels.
"Dust storm and thunderstorm with winds gusting up to 60 kilometers per hour are likely over Delhi-NCR on May 29-30," he said.
In large areas, a heatwave is declared when the maximum temperature is 45 degrees Celsius for two consecutive days and a severe heatwave is when the mercury touches 47 degrees Celsius for two days on the trot.
In small areas, like the national capital, a heatwave is declared if the temperature soars to 45 degrees Celsius even for a day, according to the IMD.