Intense heat makes Delhi sweat; mercury borders 46 degrees C in many parts

New Delhi, Apr 29 (PTI) The ongoing heatwave intensified over Delhi on Friday, with the mercury settling near 46 degrees Celsius in many parts.

The Safdarjung observatory, Delhi's base station, recorded a maximum temperature of 43.5 degrees Celsius for second day on the trot.

It is the highest maximum temperature on a day in April in 12 years.

The national capital had recorded a maximum temperature of 43.7 degrees Celsius on April 18, 2010.

The all-time high of 45.6 degrees Celsius was recorded on April 29, 1941.

The India Meteorological Department (IMD) said Delhi recorded its second hottest April in 72 years with a monthly average maximum temperature of 40.2 degrees Celsius.

In 2010, the city had recorded an average monthly maximum temperature of 40.4 degrees Celsius.

On Friday, the mercury leaped to 46.4 degrees Celsius at Sports Complex Ridge (45.7 degrees Celsius), Mungeshpur (45.9 degrees Celsius), Najafgarh (45.9 degrees Celsius) and Pitampura (45.9 degrees Celsius) recorded the maximum temperature five to seven notches above normal. The IMD has issued an "orange" alert, warning people of a severe heatwave in many parts of Delhi on Saturday.

The MeT department uses four colour codes for weather warnings -- "green" (no action needed), "yellow" (watch and stay updated), "orange" (be prepared), and "red" (take action).

Amid the rising heat and an acute shortage of coal, the Delhi government on Friday warned of power supply disruption to critical services like Metro trains and hospitals.

Chief Minister Arvind Kejriwal said his government is somehow handling the power supply situation in Delhi and called for quick and concrete steps to tackle the electricity crisis prevalent in the country.

The Delhi government has said it will supply around 1,000 million gallons of drinking water every day during the summer season as against 935 MGD earlier to meet the rising demand.

The IMD said Delhi may also see a partly cloudy sky, light rain and a dust storm with winds gusting up to 50 kilometres per hour on Sunday, which may provide temporary respite.

The heatwave is expected to abate from Monday under the influence of a western disturbance, which is likely to affect northwest India from the night of May 1, it said.

Rajasthan, Delhi, Punjab and Haryana may witness light rainfall and thunderstorm between May 2 and May 4. The maximum temperature will be between 36 degrees and 39 degrees Celsius, senior scientist R K Jenamani said.

"A maximum temperature of 45 degrees Celsius is normal at places like Churu, Barmer, Bikaner and Sriganganagar in Rajasthan, but 45-46 degrees Celsius in the plains of north India by April-end is quite unusual," independent meteorologist Navdeep Dahiya said.

The city has recorded 10 heatwave days in April, the highest since 11 such days witnessed in the month in 2010.

Delhi falls in the Core Heatwave Zone (CHZ) comprising the most heatwave-prone areas of the country along with Telangana, Andhra Pradesh, Himachal Pradesh, Uttarakhand, Haryana, Uttar Pradesh, Rajasthan, Madhya Pradesh, Maharashtra, Bihar, Chhattisgarh and West Bengal.

Northwest India has been recording higher-than-normal temperatures since the last week of March, with weather experts attributing it to absence of periodic light rainfall and thundershowers, which typify this time of the year, due to lack of active western disturbances.

The region had got some respite last week owing to cloudy weather due to the influence of a western disturbance over Afghanistan.

The IMD said the heatwave could lead to "moderate" health concerns for vulnerable people -- infants, elderly people and those with chronic diseases.

"Hence, people of these regions should avoid heat exposure, wear lightweight, light-coloured and loose cotton clothes, and cover the head with a piece of cloth, a hat or an umbrella," it said.

There is an "increased likelihood of heat-illness symptoms in people who are either exposed to the sun for a prolonged period or doing heavy work", an IMD advisory read.

For the plains, a heatwave is declared when the maximum temperature is over 40 degrees Celsius and at least four-and-a-half notches above normal.

A severe heatwave is declared if the departure from the normal temperature is by more than 6.4 notches, according to IMD.

Based on the absolute recorded temperatures, a heatwave is declared when an area logs a maximum temperature of 45 degrees Celsius. A severe heatwave is declared if the temperature crosses the 47 degree-mark.

India saw its warmest March this year since the IMD began keeping records 122 years ago amid a 71 per cent rain deficit.