Low visibility conditions disrupted flight operations at Delhi airport on Tuesday, forcing airlines to cancel a large number of services. According to a Delhi International Airport Ltd official, as many as 131 flights were cancelled due to dense fog conditions. "Due to low visibility, 52 departures and 79 arrivals have been cancelled so far at Delhi airport," the official said. Northern parts of India, including Delhi which serves as Air India's primary hub, experience severe visibility issues during winter because of dense fog. These conditions often have a cascading impact on flight schedules across airline networks, leading to widespread delays and cancellations. The Directorate General of Civil Aviation has officially declared the period from December 10 to February 10 as the fog window for the winter season.
IndiGo cancels over 100 flights
In a related development, IndiGo has cancelled as many as 113 flights across its network on Tuesday due to disruptions caused by bad weather at Delhi airport. The airline also announced that it will not operate 42 flights on Wednesday because of continued adverse weather conditions.
"As winter sets in, early mornings across northern India can bring fog that may occasionally slow down flight movements," IndiGo said in a post on X. "Our teams are well prepared and closely monitoring weather conditions," IndiGo said, adding that wherever possible, "we are making thoughtful adjustments on the ground to reduce inconvenience and ensure any waiting time is as comfortable as possible."
Special crew and aircraft needed for fog operations
Under fog operations norms, also known as CAT III B procedures, airlines are required to mandatorily deploy crew trained to operate in low-visibility conditions along with aircraft equipped for such operations. Category III is an advanced navigation system that enables aircraft to land in foggy conditions. Category III A allows landings with a runway visual range of up to 200 metres, while Category III B supports landings with visibility of less than 50 metres.
Delhi air quality into 'very poor' category
It is to be noted here that Delhi saw a marginal improvement in air quality on Tuesday as stronger winds and thinning fog pushed pollution levels out of the 'severe' category after three days, though they were still in the 'very poor' range. Delhi's 24-hour average Air Quality Index (AQI) stood at 354 at 4 pm, according to the Central Pollution Control Board (CPCB). Of the 39 active air quality monitoring stations in Delhi, only Mundka was in the 'severe' category with an AQI of 407, while 35 stations recorded 'very poor' air and three 'poor' air.
Institute of Human Behaviour and Allied Sciences (IHBAS) in Dilshad Garden recorded the lowest AQI of 280, at the higher end of the 'poor' range, according to the CPCB's Sameer app. According to the CPCB, an AQI between 0 and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor', and 401 to 500 'severe'.
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