Ten flights were cancelled at Indira Gandhi International Airport in New Delhi on the morning of December 17, 2025. Airport officials said low visibility due to dense fog caused the disruption. Meanwhile, Chennai International Airport also faced disturbances with 11 flights cancelled the same morning. According to an official statement, four departing and seven arriving flights were cancelled. The cancellations happened because fog, bad weather, and pollution have affected flights in New Delhi and northern states for several days. The statement added, "Flight services in New Delhi and other northern States have been severely impacted due to dense fog and adverse weather conditions. Several flights bound for New Delhi were unable to land and were diverted to other airports." Flight services between Chennai and northern cities also faced problems. Four flights from Chennai to cities including New Delhi, Jaipur, Kolkata, and Ghaziabad were cancelled. Seven arriving flights to Chennai from Delhi, Jaipur, Patna, Pune, Kolkata, Indore, and others were also cancelled. These cancellations caused major inconvenience to travelers. Meanwhile, Delhi saw a slight improvement in air quality on the morning of December 17. The Air Quality Index was 328 at 8 a.m., which is still in the 'very poor' category, as per data from the Central Pollution Control Board. This is a small improvement from the previous day when the AQI reached 354 at 4 p.m. Despite the better numbers, much of Delhi remained covered in toxic smog with poor air quality continuing. The CPCB categorizes air quality as 'good' (0-50), 'satisfactory' (51-100), 'moderate' (101-200), 'poor' (201-300), 'very poor' (301-400), and 'severe' (401-500).