Toxic smog blurs visibility in Capital; 228 flights cancelled

AHeavy piece of paper of toxic fogginess held the working capital in a choke hold on Monday, sending visibility plummeting to zero in swathes of the city, disrupting road and rail traffic, and causing over 800 flights to be delayed and another 228 cancelled as of 10pm, despite recent airport upgrades.The first ‘dense to very dense’ fog of the season blanketed a city already gasping for breath in air that remained in the severe category for a third consecutive day. The 24-hour average air quality index (AQI) stood at 427 at 4pm – marginally lower than Sunday’s reading of 461, which was December’s second worst air day ever.Also Read | Rekha Gupta greeted with 'AQI, AQI' chants during Messi event as smog engulfs DelhiThe noxious cocktail forced the Delhi government to shift schools from hybrid to online mode for students up to Class 5 but there was little respite for the Capital’s 25 million residents caught between official apathy, poorly designed response systems, and a long winter in front of them.The India Meteorological Department (IMD) issued a yellow alert for Tuesday, forecasting moderate fog in the early hours of the day, with dense fog for isolated pockets. However, strong surface winds of 15-25 km/hour are forecast during the day, which might help with dispersion of pollutants.The grey skies over Delhi bore a grim reflection of the weekend, when surface pollutants stayed trapped under slow winds, dipping temperatures, and an “inversion” layer, even as a weak sun failed to disperse them. Residents continue to complain of laboured breathing and burning eyes — which have now become all too normal — and the weather conditions served as a reminder of collapsing systems that fail to mitigate the yearly health crisis that descends on the Capital.This was the sixth straight severe air day this year. Three such days came between November 11-13.The IMD classifies fog as shallow when visibility is between 500-1000 metres, moderate when visibility is between 200-500 metres, as dense when it is between 50 and 200 metres and as very dense when visibility dips below 50 metres.At Safdarjung, dense fog persisted for over 10 hours, while at Palam, it was recorded for around five hours. “Visibility began to dip rapidly on Sunday night itself. It was down to 150 metres at 11.30pm and by 12.30am on Monday, had already touched zero at Safdarjung. It remained zero till 2am, only improving marginally to 100 metres at 2.30am. At Palam, we saw the lowest visibility dip to 50 metres at around 4am,” said an IMD official, stating that wind speed remained low, facilitating fog formation.The low visibility threw operations at the Indira Gandhi International Airport – which has barely recovered from the scheduling meltdown of IndiGo that grounded tens of thousands of passengers earlier this month – into disarray. Departures were put nearly on hold for close to five hours between 4am and 9am despite all three runways notionally equipped to handle winter fog situations. The cascading effect of the morning crisis reverberated throughout the day, leaving hundreds of passengers either stranded or desperate after hours of delay. In all, the airport saw 800 flights delayed through the day, 228 cancelled and five diverted.Also Read | AQI soars, will Delhi turn to artificial rain? What happened to the cloud seeding trialsSenior Supreme Court lawyer Sanjay Hegde was among those impacted by flights not taking off due to low visibility. “Woke up at 5.00 AM to catch a 7.45 AM flight. Still sitting on the tarmac waiting for ATC clearance and informed that there are 40 aircraft in the queue ahead of us. An airhostess chirps that there are aircraft waiting for over 4 hours now on the tarmac,” he wrote on X.Low visibility procedures were initiated at the airport at around 2.30am. Flight disruptions intensified after 4am, when visibility dropped to around 100 metres. “Due to dense fog, flight operations may experience disruptions,” Delhi airport said in a post on X at 6.12am. A subsequent update at 8.22am said the airport remained under CAT-III operations, with delays and disruptions likely to continue. Even after fog began lifting around midday, flight delays persisted due to accumulated congestion.By evening, operations had begun stabilising, though delays continued to ripple through the system. “Flight operations are gradually returning to normal. However, some departures and arrivals may still experience delays,” the airport said in an update at 4.10pm.Among the affected was Argentine football legend Lionel Messi, who was scheduled to depart from Mumbai early morning and reach Delhi by 11am. But he could only make it to the Capital by 2.30pm as his chartered flight was held up by fog.Officials said that despite the recent upgrade of a third runway to CAT-III standards ahead of the winter fog season, take-offs – and not landings – proved to be the main bottleneck. CAT-III allows aircraft to land safely in extremely low visibility.“Aircraft can land even when the runway visual range (RVR) is as low as 50 metres. But for take-offs, a minimum RVR of 125 metres is required,” an airport official said. “From around 4am, the RVR remained below that threshold. Aircraft had to wait at parking bays, which led to congestion. Only two take-offs were possible till around 9am.”While landings continued through much of the early morning, the congestion on the ground eventually forced a slowdown, compounding delays across terminals and runways.Airlines said cancellations were largely precautionary to reduce chaos at airports. “While operations adjust to the prevailing weather, some flights may experience delays while a few others may be proactively cancelled through the day to prioritise safety and help minimise extended waiting at the airport,” IndiGo said. Air India issued a similar statement, adding poor visibility due to dense fog in Delhi had hit operations. “In the interest of safety, and to avoid prolonged uncertainty for our guests, some flights have been cancelled,” it said on X.Separately, Northern Railways reported over 90 trains delayed by between 30 minutes to five hours. At least four people died due to multi-vehicle pile-ups on the Delhi-Mumbai Expressway near Haryana’s Nuh. A 24-year old sustained critical injuries in a ten vehicle crash on the Eastern Peripheral Expressway (EPE) in Greater Noida in the early hours.The IMD official cited above said the visibility improved after 9-9.30am. “At Safdarjung, visibility improved to 300 metres at 9.30am and by 10.30am, had improved to 700 metres as the sun began to come out. At Palam, it was 100 metres at 9am but improved to 300 metres at 10.30 am and further to 500 metres by noon,” the official added.The alarming spike in pollution over the weekend was due to more localised NCR sources, as opposed to poor meteorological conditions, stubble smoke and Diwali that hurt Delhi’s air quality in November. On Monday, 28 out of the city’s 39 active ambient air quality stations were in the ‘severe’ category at 5pm – down from 38 such stations on Sunday.However, the peak impact did not change much, particularly in the early hours. Two stations – Rohini and Wazirpur – maxed out with an AQI of 500 in the early hours of the day.Forecasts by the chronically unreliable Centre’s Air Quality Early Warning System (EWS) suggested possible respite ahead – but not by much. “Delhi’s air quality is likely to improve and will reach the ‘very poor’ category from December 16-18. The outlook for the subsequent six days from December 19 also shows AQI is likely to be in the ‘very poor’ category,” it said. To be sure, EWS has missed its mark multiple times this season, including its forecasts for December 13 and 15, when it had forecast ‘very poor’ air.