India's civil aviation minister says a black box has been found at the Air India plane crash site in Ahmedabad
All but one of the 242 people on the London-bound flight died when it crashed into a residential area shortly after take-off on Thursday
It is not yet clear how many people on the ground were killed - an official tells the BBC at least eight have died
The sole survivor, British national Vishwashkumar Ramesh, who was in seat 11A, is recovering in hospital and says: "I still cannot believe how I made it out alive"
There were 169 Indian nationals, 53 Britons, seven Portuguese nationals and one Canadian on the flight, Air India says
A doctor tells the BBC they are relying on DNA matching from families to identify victims, as relatives wait anxiously for news
'I don't believe it yet': Passengers' families wait for answers
Fifty-three British nationals were on board the flight bound for Gatwick airport, Air India says.
Details of other nationalities on board are still coming in.
We now have a statement from DGCA, India's aviation regulator, which says the flight "crashed immediately after take-off from Ahmedabad". The statement says:
A spokesperson from the Sardar Vallabhbhai Patel International Airport in Ahmedabad says the airport is currently not operational. All flight operations are suspended until further notice.
BBC Verify has been looking at what flight tracking data shows about the plane's take-off.
The Boeing 787-8 Dreamliner took off from Ahmedabad at 13:38 local time (09:08 BST) en route to London Gatwick.
In the image below, you can see how the plane moved to the end of the runway. Flight tracking data ends with the plane at an altitude of 625ft (190m).
We’re currently looking at footage posted online of the crash and its aftermath.
Image source, Flight RadarFaiz Ahmed Kidwai, chief of India's directorate of civil aviation, tells the Associated Press the plane crashed into a residential area called Meghani Nagar.
There were 232 passengers and 12 crew members on board, he says.
The chief minister of Gujarat says officials have been instructed to carry out "immediate rescue and relief operations" and to make arrangements on a "war footing".
"I have also instructed officials to arrange a green corridor to transport the injured passengers for treatment and to ensure all necessary medical arrangements are made at the hospital on priority," Bhupendra Patel writes on X, external.
In a statement posted on X, Air India's chairman, Natarajan Chandrasekaran, says "with profound sorrow I confirm that Air India Flight 171 operating Ahmedabad London Gatwick was involved in a tragic accident today".
"Our thoughts and deepest condolences are with the families and loved ones of all those affected by this devastating event," he says.
"At this moment, our primary focus is on supporting all the affected people and their families.
"We are doing everything in our power to assist the emergency response teams at the site and to provide all necessary support and care to those impacted.
"Further updates will be shared as we receive more verified information. An emergency centre has been activated and support team have been set up for families seeking information."
Gatwick Airport confirms the plane travelling from Ahmedabad was due to land at 18:25 BST.
In a statement on X, Gatwick Airport says: "We can confirm that flight AI171 that crashed on departure from Ahmedabad Airport today was due to land at London Gatwick at 18:25."
We are now getting images from the scene, showing black smoke billowing from the site of the crash.
Image source, APMore now from Kinjarapu Ram Mohan Naidu, India's aviation minister.
"We are on highest alert. I am personally monitoring the situation and have directed all aviation and emergency response agencies to take swift and coordinated action.
"Rescue teams have been mobilised, and all efforts are being made to ensure medical aid and relief support are being rushed to the site. My thoughts and prayers are with all those on board and their families."
India's Aviation Minister Kinjarapu Ram Mohan Naidu says he is "shocked and devastated" at the crash in Ahmedabad.
We'll bring you more from his statement shortly.
Rich Preston
BBC News
The aircraft that crashed is a Boeing 787-8 Dreamliner with registration VT-ANB, according to Flightradar24.
SeatGuru says the plane has a total of 256 seats on board - it's not known exactly how many of those were occupied.
It was scheduled to land at 18:25 BST at Gatwick.
The plane's history shows it regularly flies between India and destinations including Paris, Frankfurt, Tokyo, Amsterdam, and Melbourne.
India's aviation regulator says the aircraft crashed "outside the airport perimeter" after take-off, Reuters news agency reports.
More now from flight-tracking website Flightradar24, which earlier said the signal was lost seconds after take-off.
Flightradar24 says the Air India flight was scheduled to fly from Ahmedabad International Airport to London Gatwick Airport at 13:10 local time (IST). Its scheduled arrival time was 18:25 BST.
The signal was lost at 13:38 local time at 625ft, less than a minute after take-off.
India's aviation minister says "we are on highest alert", as "rescue teams have been mobilised".
The plane is understood to have been carrying more than 200 passengers.
The flight tracking website, Flight Radar, says on X: "We are following reports of a crash of Air India flight #AI171, external from Ahmedabad to London.
"We received the last signal from the aircraft at 08:08:51 UTC, just seconds after take off."