Explainer: What’s behind bomb threats that have disrupted 100 flights in India?

Hoax bomb threats have disrupted nearly 100 flights in India over the past week and rattled the country’s aviation sector.

The wave of threats, issued mostly via X, has alarmed passengers and sent the aviation authorities scrambling to mount a response.

At least 30 of the threats were received on Saturday alone and another dozen the next day. All turned out to be hoaxes.

A Vistara flight bound for Frankfurt was compelled to return to Delhi on Sunday after Afghanistan reportedly denied it permission to fly through due to a bomb threat.

Flight UK25, carrying over 240 passengers, had left Delhi at 1.10pm local time. Since the threat was deemed “non-specific”, the initial plan was for it to continue the journey to Germany, the news agency PTI reported, citing unnamed sources.

But the Afghan authorities refused to allow the Boeing 787 to enter their airspace, forcing it to return to Delhi after circling briefly over Pakistan and Afghanistan, according to flight tracking data from Flightradar24. The plane landed safely at about 4.20pm local time.

UK25 typically flies over Pakistan and Afghanistan on the way to Frankfurt.

“Flight UK25 from Delhi to Frankfurt is returning back to Delhi and is expected to arrive in Delhi at 1620 hours,” the airline confirmed on X.

Another three Vistara Airlines flights had received similar threats on Saturday morning. While a flight from Delhi to London was diverted to Frankfurt in view of the threat, the other flights landed safely at their destinations in Paris and Hong Kong.

A few days earlier, a Vistara flight arriving in Mumbai from Frankfurt with 147 passengers and crew had to make an emergency landing and undergo security checks in an isolation bay after a bomb scare.

An Air India flight from Mumbai to New York had to be rerouted to Delhi, evacuated, and searched for explosives. The plane was forced to dump nearly 100 tonnes of jet fuel to ensure a safe landing, costing the airline around Rs10mn (£91,210), the Times of India reported. The total cost of the diversion, including accommodation for passengers, grounding of the aircraft and crew replacements, was expected to exceed Rs 30 mn (£273,626).

A similar threat had forced an Air India Boeing 777 flight to Chicago to make an emergency landing in Canada, stranding over 200 passengers for over 18 hours at a…