IndiGo flight 6E6504 left Agartala for Delhi on 15 September and landed at Lucknow at 18.29 with 103 passengers and six crew. The crew turned because a smoke warning came from the cargo area. Airport fire, rescue, ambulance and terminal teams were waiting. Officials said everyone left the aircraft without injury and that no further incident was reported on the ground. That is all that is confirmed. A warning is not a photograph of fire. It is a light and a procedure. Until engineering opens the hold, the only safe assumption in the air is that the indication might be real.
Cargo compartments on modern jets are built to contain a fire long enough for the crew to land. Detectors watch for particles or heat. Bottles can dump agent into a closed hold. The checklist does not ask the captain to decide whether the sensor is moody. It asks for the nearest suitable field, a PAN or mayday as required, preparation of the cabin, and an overweight or normal landing with emergency services rolled. Lucknow sits under the Agartala-Delhi track with a long runway and a full ARFF category. Continuing to Delhi with an unresolved cargo indication would have added time in a sealed box the crew cannot see. That is why the diversion looks dramatic from the terminal and ordinary from the jump seat. The same airport has already received Air India Express cargo-smoke diversions this month, including IX1253 from Varanasi on 3 September, when first checks found no visible smoke. Recurrence at one field does not prove a common defect. It does prove that crews are treating the alert as designed.
What is still missing is the part passengers deserve next. IndiGo and DGCA have not published the type or registration, the detector’s exact message, or whether the hold held a bag, a battery, a wiring fault or a false alarm. They have not said whether the same aircraft flew on or was replaced. Those answers belong in an occurrence report, not in a rumour that the cabin was on fire. The useful lesson is already on the ground at Lucknow. When the cargo light comes on, the aircraft leaves the airway and the airport treats it as a possible fire until someone proves it is not.