The incident happened on Saturday.
The development also comes days after the airline had apologised to a passenger who was manhandled at Delhi airport in October.
"We apologise to Ms. Urvashi Parikh Viren for the mishap which occurred at the Lucknow Airport yesterday at 8 p.m.," the airline said in a statement.
— IndiGo (@IndiGo6E) November 7, 2017
"Our IndiGo representative was pushing her wheelchair towards the arrival hall. As he was guiding her wheelchair through a vehicular lane, which was dimly lit at that time of the night, her wheelchair got stuck in a deep crack on the tarmac and lost balance and she fell off her wheelchair."
"Parikh was injured and immediately rushed to the doctor of the Airports Authority of India. He administered first aid to her."
According to the airline, the passenger was kind enough to say that it was not a human error and "we should deal with the staff with empathy, when we de-brief our loader. We promised to do so."