Besides Delhi, the alert, which is the highest in the IMD's four colour-coded warnings, was issued for Punjab, Haryana, Chandigarh, Rajasthan and some parts of Uttar Pradesh.

The department said that on Saturday a severe heatwave condition will prevail in Delhi especially in isolated pockets and maximum temperature is likely to hover around 45 degrees Celsius.

Heatwave will continue in the region for another five days.

According to the IMD, a heatwave is considered if the maximum temperature reaches at least 40 degrees Celsius or more for plains, 37 degrees for coastal ares and at least 30 degrees for hilly regions.

The IMD alert came after it observed heatwave conditions in Delhi, Chandigarh, Uttar Pradesh, Rajasthan and some parts of Madhya Pradesh on Thursday.

On Friday, Delhi recorded a maximum temperature of 44.8 degrees Celsius, four notches above the season's average, while the minimum was 28.4 degrees, a notch above the normal.