Viral fake News:
Indira Gandhi changed her name to Maimoona Begum, post her marriage with Feroz Khan and she practised Islam. She purposefully hid the fact, due to political reasons and tried to retain the name 'Indira Gandhi' in public.
Truth turns out:
It was widely rumored that the former Prime Minister of India Indira Gandhi's husband Feroz Gandhi, changed his name and religion. It was rumoured that Feroz Gandhi is actually 'Feroz Khan' and is a Muslim.
Indira Gandhi, daughter of Jawaharlal Nehru, was born in a pandit family. There isnt any factual evidence of her conversion to Islam even in her biography "Pupul jayakar".
On the other hand, Feroz Gandhi is a parsi. Parsis have their origin from Iran. Feroz Gandhi's father Jahangir Faredoon Ghandy was a marine engineer, believed to have born in Gujarat and later migrated to Mumbai. Feroz Gandhi involved himself in Indian politics and was one of the leaders in the Indian Congress.
Hence the above rumour about Feroz Gandhi and Indira Gandhi, can be concluded as a fake news and is politically motivated.