Indian police have arrested a drill instructor who pushed a university student from the ledge above the second floor of a building to her death during a bungled training exercise, officials said on Friday (July 13).

Horrified onlookers watched as the 19-year-old struck a concrete landing after being shoved off a ledge by the instructor.

A crowd of students positioned below with a crash net could only watch as the young student cracked her head violently in the awkward fall before tumbling to the ground.

The whole incident was captured on video and provoked outrage after the footage went viral on social media.

"She sustained fatal injuries on her neck and head. The trainer has been charged with causing death due to negligence," said the officer, who requested anonymity as he was not permitted to talk to the media.

The National Disaster Management Authority (NDMA), which stages mock disaster drills across India, said it did not organise or sanction Thursday's event.

"The trainer wasn't authorised by NDMA to conduct such a drill," the authority said on Twitter.

Local media reports said the instructor was not certified to perform such a drill and college authorities had not sought official permission to stage the exercise.