Purnima Rathi, 32, and her daughter Mamta were being treated for minor injuries at a hospital in nearby Khopoli town, about 100km from Mumbai, they said.
They were injured when the roller coaster ride was stopped suddenly due to some technical issue, police said without giving details.
But photographs reveal that the roller coaster actually went off the tracks.
The incident occurred at around 1 pm on the 'Bandits of Robin Hood' ride, and both victims were immediately taken to the hospital, Adlabs Imagica said in a release.
Ashutosh Kale, Assistant Vice-President (Safety and Security), Adlabs Imagica, said that three test runs had been carried out on the ride before opening it for the guests.
He, too, did not disclose how the incident occurred.
The Rs 1,600-crore theme park, spread over 300 acres and located off Mumbai-Pune Expressway, opened for public in April last year.
Photograph: An image of the mishap circulating in social media
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