Dense fog made a return to Delhi and nearby cities like Ghaziabad and Noida on Friday morning, causing visibility in some areas to drop to zero. This prompted Indira Gandhi International Airport (IGI) to issue a warning about possible flight disruptions. The dense fog arrived alongside a significant decline in the Air Quality Index (AQI) across Delhi-NCR. As of 6:05 am, Delhi’s AQI was measured at 409, falling in the ‘severe’ category, according to the Sameer app that provides real-time air quality data.
Although the exact number of flights and trains affected by the fog was not immediately clear, reports indicated that over 100 flights had been delayed at IGI Airport. At 5:30 am, the temperature in Delhi was 9.6 degrees Celsius, with the India Meteorological Department (IMD) forecasting a minimum temperature of around 6 degrees Celsius and a maximum of 20 degrees Celsius, accompanied by very dense fog.
In response to the conditions, IGI Airport issued an advisory at 4:25 am urging passengers to check with their airlines for updates on flight statuses. A follow-up notice at 5:52 am confirmed disruptions to flight departures, though flights adhering to Category III (CAT III) protocols were still able to operate. IndiGo also took to social media at 5:04 am, advising passengers to stay informed about the status of their flights before heading to the airport.
Delhi and surrounding cities like Noida, Ghaziabad, and Gurugram had previously experienced similar dense fog conditions between January 2 and 3, when visibility was reduced to zero for an extended period of up to nine hours—the longest stretch of the season according to the weather department. On Thursday, after several chilly and breezy days, Delhi experienced a sunny afternoon with a maximum temperature of 21.2 degrees Celsius, slightly above the seasonal average. However, the morning temperature was colder, at 4.8 degrees Celsius, compared to 7.4 degrees Celsius the previous day.
Meanwhile, the worsening air quality led the Centre’s air quality management panel to reinstate Stage 3 restrictions under the Graded Response Action Plan (GRAP). The AQI in Delhi had surged to 357 at 4 pm on Thursday, up from 297 the previous day, due to the combination of stagnant air and foggy conditions. The Commission for Air Quality Management (CAQM) directed authorities to enforce Stage 3 curbs to prevent further air pollution. These measures include a ban on non-essential construction work.
The AQI scale categorizes levels from 0-50 as ‘good,’ 51-100 as ‘satisfactory,’ 101-200 as ‘moderate,’ 201-300 as ‘poor,’ 301-400 as ‘very poor,’ and 401-500 as ‘severe.’
In a related report, the Centre for Research on Energy and Clean Air (CREA) noted a 12 percent reduction in air pollution levels in Delhi compared to 2017. PM10 levels decreased from 241 µg/m³ to 211 µg/m³, but the city still fell short of its target. The report also highlighted that only 31 percent of the 131 non-attainment cities identified under the National Clean Air Programme (NCAP) had successfully reduced PM10 levels by 20-30 percent by 2024, as required.
