Five passenger on board an Air India flight from London to Mumbai have fallen ill after experiencing some scary symptoms on board the jet.

The flight on Monday also saw two more passengers and two crew members fall ill after landing in India, and needed medical assistance from teams on the ground. All nine people from flight AI 130 suffered with nausea and dizziness, which was believed to have been caused by a decrease in cabin pressure.

The airline confirmed the incident, saying that five passengers and two crew members took ill. Two passengers and two crew members continued to feel ill after the flight landed in Mumbai. They received medical assistance and were later discharged. The cause of the incident is under investigation, the airline said.

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An Air India source, speaking to the Hindustan Times anonymously, said the passengers and crew fell sick due to slow decompression, or a gradual decrease in cabin pressure. They added: "A few of them were taken to the medical room (at Mumbai’s Terminal 2) in wheelchairs."

The sources added that the pilots were not affected by the sickness that gripped multiple passengers and crew.

An Air India spokeswoman said: "On board flight AI-130 from London Heathrow to Mumbai, five passengers and two crew reported feeling dizzy and nauseous during different phases of the flight.

"The flight landed safely in Mumbai where our medical teams were ready to provide immediate medical assistance.

"After landing, two passengers and two cabin crew, who continued to feel unwell, were taken to the medical room for further examination and were later discharged. We are investigating the incident and have duly notified the regulator."

On Thursday, June 12, a total of 270 people, including all but one of the 242 passengers on board, died when the Air India Boeing Dreamliner plane plummeted to the ground in Ahmedabad, India after just 40 seconds in the air.

Authorities have since launched a probe into what caused the crash - and are now said to have found evidence that an emergency generator may have the aircraft's primary power source at the time it went down.

One leading theory is that the plane suffered a dual engine failure, though what triggered this is yet to be determined.

The reported activation of an emergency generator, known as a ram air turbine, could suggest that there were problems with the engines at the time the plane took off.

It comes after British families of Air India crash victims were said to be facing "pain and frustration" over delays in the identification and repatriation of their relatives.

Relatives of Akeel Nanabawa, his wife Hannaa Vorajee and their four-year-old daughter Sara Nanabawa, who died in the crash, said they felt "utterly abandoned" by the UK Government and called for more support on the ground in India.