Dust storm takes city by surprise, trace rain brings down mercury

Delhi on Tuesday logged a maximum temperature of 36.8°C, one degree below normal and down from 37.6°C a day before. The minimum temperature was 22.6°C, a minor dip from 23°C logged on Monday

A dust storm with strong surface winds of up to 50kmph lashed Delhi in a 30-minute spell on Tuesday evening, accompanied by a drizzle and thunderstorms, bringing the Capital temporary relief from the heat, said officials of the India Meteorological Department (IMD).

A dust storm hit the city on Tuesday evening, followed by a spell of rain and sunshine, leading to rainbows in the capital skies. (Vipin Kumar/HT Photo)

The unfavourable weather conditions also affected flight operations. Officials at the Indira Gandhi International Airport said that 15 flights were diverted from Delhi due to inclement weather. Of these, nine were diverted to Jaipur, two to Amritsar, two to Lucknow, and one each to Mumbai and Chandigarh.

According to a report shared by the Municipal Corporation of Delhi late evening, waterlogging was reported in Vasant Vihar, Kalkaji, Badarpur and Patparganj. An incident of tree falling was also reported, from Janakpuri, due to the wind and subsequent rain.

IMD had, in its weekend forecast, predicted gusty winds for the week, it did not forecast a dust storm. The Safdarjung weather monitor — considered representative of Delhi’s weather — recorded trace rain between 8.30am and 5.30pm. Palam, Mungeshpur and Jafarpur received 9.5mm, 1.5mm and 0.5mm of rainfall, respectively, and the stations at Ridge and Ayanagar logged trace rain.

“This was the first dust storm of the year. Several parts of Delhi got rain and thunderstorms, but these will clear out completely by Wednesday. Dust storms are pretty common in Delhi during summer,” said Kuldeep Srivastava, a scientist at IMD.

“This has a lot of contributing factors. High temperature and high humidity for a continued period, as well as cyclonic circulation from south Haryana and northeast Rajasthan, have led to dust storms,” said Srivastava.

“An active western disturbance has had a consistent impact, but wasn’t the primary cause of Tuesday’s dust storm. This western disturbance, primarily coming from Pakistan and adjoining areas of Jammu & Kashmir, might impact the weather again over the weekend,” Srivastava said.

Delhi on Tuesday clocked a maximum temperature of 36.8°C, one degree below normal and down from 37.6°C the previous day. The minimum temperature was 22.6°C, a minor dip from 23°C on Monday.

According to IMD’s weekly forecast, the temperature will increase gradually through the week, with the maximum and minimum touching 40°C and 25°C, respectively, by the weekend. Delhi is forecast to have mostly clear skies till Thursday, followed by partly cloudy skies.

“Strong surface winds might continue for the next few days,” a Met official said.

Meanwhile, Delhi’s air quality deteriorated significantly on the day, but stayed in the higher echelons of the “moderate” category. Experts said dust storms do not primarily contribute to air quality index.

Mukesh Khare, a professor at the Indian Institute of Technology (IIT) and an air quality modelling expert, said, “Dust storms mostly contain PM10, which are coarser particles in the air, while air quality index (AQI) is calculated mostly on the basis of PM2.5 and other particulate matter.”

As of 4pm on Tuesday, Delhi’s AQI was 188, worse than 127 on Monday and 138 on Sunday, according to the Central Pollution Control Board’s national bulletin.

Forecasts by the early warning system (EWS) for Delhi — a forecasting model under the ministry of earth sciences — said Delhi’s air quality would remain “moderate” till April 26.

“The air quality is likely to be in moderate category from April 24 to April 26. The outlook for subsequent six days is that the air quality is likely to be in moderate category,” the EWS in its daily bulletin on Tuesday.