Rain, thunderstorms likely as IMD issues yellow alert for Delhi

A spell of very light to light rain is expected on Sunday as well, with more widespread rain likely on Monday and Tuesday, according to the IMD

The India Meteorological Department (IMD) on Saturday issued a yellow alert for Monday, forecasting light to moderate rain accompanied by thunderstorms and gusty winds reaching speeds of up to 40–50km/hour. Officials said scattered showers on Sunday and more widespread rain early next week are expected to help clear pollutants from the Capital’s air, which slipped back to the ‘moderate’ category on Saturday after a brief spell of cleaner air.

Morning smog blankets Kartavya Path in New Delhi, on Saturday. (Arvind Yadav/HT Photo)

“A spell of very light to light rain is expected on Sunday as well, with more widespread rain likely on Monday and Tuesday,” said an IMD official, adding that the precipitation could bring minimum and maximum temperatures down by a couple of degrees.

Delhi’s 24-hour average air quality index (AQI) on Saturday stood at 138 at 4pm, according to the Central Pollution Control Board’s (CPCB) daily bulletin. The day before, the city had recorded an AQI of 88 — its lowest post-Dussehra level in three years — following rain and strong winds that helped disperse pollutants. Friday’s ‘satisfactory’ air quality had also ended a 21-day spell of ‘moderate’ conditions.

Meteorologists said the marginal deterioration on Saturday was due to a drop in wind speed and the absence of rainfall. “The wind speed reduced slightly on Saturday, leading to an increase in pollution levels. However, some rain is expected on Sunday, with a higher possibility of light to moderate showers on Monday and Tuesday, which will help in dispersal of pollutants,” said Mahesh Palawat, vice-president (meteorology and climate change), Skymet Weather.

Forecasts by the Air Quality Early Warning System (AQEWS) for Delhi suggest that the AQI will remain in the ‘moderate’ range on Sunday and improve to ‘satisfactory’ from Monday onwards. “The outlook for the subsequent six days suggests air quality will fluctuate between the satisfactory and moderate categories,” the AQEWS bulletin stated.

According to CPCB data, concentrations of PM2.5 — the most harmful pollutant — averaged around 65 micrograms per cubic metre across Delhi on Saturday (till 9pm), 5µg/m³ above the national safe limit of 60 µg/m³ but much lower the 204-263 µg/m³, which are the typical October-end levels in Delhi over in the past three years.

On Saturday, humidity in the city fluctuated between 63% and 100%, and no rainfall was recorded. The maximum temperature settled at 34.0 °C, which was below normal, while the minimum was 24.6°C, which is 2.3 degrees above normal.