A Delhi-bound Air India Express flight from Bagdogra (Siliguri) made an emergency landing at the Chaudhary Charan Singh International Airport here after a smoke alarm, sources said on Tuesday.The flight (IX1523), operated by an Airbus A320 aircraft, was diverted to Lucknow on Monday evening after the pilot issued a ‘Mayday’ call – an internationally recognised distress signal used in life-threatening emergencies – after the crew detected smoke in the avionics or aviation electronics bay.According to sources, Air Traffic Control (ATC) in Lucknow was alerted about the diversion, and the aircraft landed safely at 5.18 pm.A total of 148 people, including six crew members, were on board the flight.All passengers were safely evacuated after landing.The aircraft was declared ‘Aircraft on Ground’, a technical term indicating that the plane has been grounded due to a fault requiring immediate inspection and repair before it can fly again.Passengers were accommodated on alternative flights to their destination.Some passengers were offered full refunds, while others were provided hotel accommodation and rebooked on subsequent flights, sources said.The aircraft remains parked at the Lucknow airport.