Heatwave alert in Delhi for next 3 days as AQI remains ‘poor’

Heatwave conditions are expected in parts of the national Capital beginning Monday till Wednesday, with the maximum likely to hover around 40-42°C, the India Meteorological Department (IMD) has said. Air quality in the city also continues to remain in the ‘poor’ category.

According to IMD, a heatwave is declared when the maximum temperature is at least 40°C and also 4.5°C or more above normal. Alternatively, any day when the maximum crosses 45°C or higher also qualifies as a heatwave.

A ‘severe’ heatwave is one where the maximum is 6.5°C above normal.

On Sunday, Safdarjung — Delhi’s official weather station — recorded a maximum of 38.2°C, which was 3°C above normal. It was 35.7°C a day earlier. The highest maximum recorded at Safdarjung so far this season was 39°C on April 3.

The minimum at Safdarjung was 20.2°C on Monday morning, which was around normal for this time of the year. It was 18.5°C on Sunday and 17.5°C on Saturday.

A further rise in minimum temperature is likely on Tuesday, with it expected to be between 21-23°C.

“With clear skies expected in the region, daytime temperatures on the rise. Conditions are conducive for a heatwave across the city,” an IMD official said.

Also Read:IMD issues ‘yellow alert’ for Delhi over next 3 days; heatwave stretches across north India

Mahesh Palawat, vice president of Meteorology at Skymet, added that the combination of clear skies and warm, light south-easterly are all expected to push temperatures higher.

“Some relief may be seen after April 10, when cloud cover under the influence of a western disturbance could bring down the mercury,” he said.

While parts of the capital have already seen 40°C breached this season, Safdarjung is yet to record a 40°C day this year.

Historically, the bulk of Delhi’s heatwave days fall between mid-April and early June. IMD records show no heatwave at Safdarjung in April last year, although five such days were logged in May.

Historical data also shows the maximum has crossed 40°C every April since 2012, when the highest maximum in the month was only 38.7°C.

Last April, the highest maximum was 40.5°C (April 5). In 2023, it was 40.6°C (April 18) and 43.5°C in 2022 (April 29 and 30). The all-time high for April is 45.6°C, which came on April 29, 1941.

Meanwhile, the city’s air quality remained in the ‘poor’ category on Monday with average air quality index (AQI) staying at 237 (poor) at 10am on Monday. In comparison, it was 209 (poor) at 4pm on Sunday.

Forecasts by the Air Quality Early Warning System for Delhi (EWS) under the Ministry of Earth Sciences show the AQI could remain ‘poor’ until April 8, before improving to ‘moderate’ levels on April 9.

The CPCB classifies AQI between 0 and 50 as ‘good,’ between 51 and 100 as ‘satisfactory,’ between 101 and 200 as ‘moderate,’ between 201 and 300 as ‘poor,’ between 301 and 400 as ‘very poor,’ and over 400 as ‘severe’.