The GoAir plane, carrying 150 passengers, was en route from the eastern city of Bhubaneshwar to Mumbai when authorities received an anonymous call that a bomb had been planted aboard.
“Post receiving the bomb threat call, (the aircraft) was diverted to Nagpur,” GoAir said in an emailed statement.
The passengers were offloaded and airport security searched the aircraft and baggage, the budget airline said.
It said “there was no bomb found on board the aircraft” and passengers “are now being boarded” after the plane was authorised to take off again for Mumbai.
The carrier said local police were investigating the threat.
The emergency landing comes one day after India’s counter-terror police arrested a group of suspected Islamist radicals in a series of nationwide raids.
The National Investigation Agency said on Friday that bomb-making material was also seized in the raids conducted in four different states, amid stepped up security for next week’s Republic Day celebrations.
French President Francois Hollande will be the guest of honour at a Republic Day military parade on Tuesday in the capital New Delhi.
Republic Day marks the anniversary of India’s democratic constitution taking force in 1950.