LUCKNOW: A full-scale emergency was declared at Lucknow’s Chaudhary Charan Singh International Airport (CCSIA) on Monday evening after an Air India Express flight operating from Bagdogra to Delhi issued a Mayday call mid-air following suspected smoke inside the aircraft.The flight, IX 1523, was cruising at 36,000 feet above Ghaghara river in Ambedkar Nagar district at around 4.58 pm, when pilots claimed to have detected, as what they believed to be smoke emanating from the aircraft’s avionic panels in the cabin and immediately informed air traffic control.“As a precautionary measure, the crew declared a Mayday, triggering the deployment of oxygen masks and causing panic among a section of passengers,” said a source familiar with the incident.Several passengers later said the sudden drop of oxygen masks, combined with the Mayday announcement, led to moments of fear and confusion inside the aircraft. Some passengers reported that anxiety spread quickly as cabin crew rushed to reassure travelers and calmly guided them on how to use the masks while the aircraft prepared for diversion.Following the alert, the aircraft was diverted to Lucknow and made a safe precautionary landing at CCSIA at 5.17 pm. Emergency response teams, including airport fire and medical services, were positioned in advance as part of standard protocol for such situations.All 148 passengers and crew were safely deboarded and escorted to Terminal 3. Officials said no injuries were reported. A detailed inspection of the aircraft was carried out by the airport fire department and technical teams, but no visible signs of smoke or fire were found.Despite the absence of any immediate findings, the aircraft has been grounded as a safety measure and will return to service only after a comprehensive technical evaluation and formal certification of airworthiness.The incident triggered frustration among some passengers due to delays and uncertainty about onward travel. One passenger, identified as Hemron Michael, shared an image of the oxygen mask deployment on social media, seeking clarity on revised travel arrangements as the delay extended beyond two hours.According to officials from Lucknow International Airport Ltd, passengers were initially brought to Terminal 3. A number of them were accommodated on alternate flights to Delhi, while others were provided overnight hotel accommodation and assured priority booking on the next available flights.Airport officials reiterated that the emergency procedures followed during the incident ensured passenger safety, noting that precautionary diversions and grounding of aircraft are standard practice when potential technical issues are reported mid-flight.