The girl identified as Shreya Shruti a class XII student of the DAV NIT school under Adityapur police station, took the extreme step as she did not fare well in her Mathematics and Science subjects, they said.
Shreya leapt from the fifth floor of the residential apartment situated near the main thoroughfare on Sher-E-Punjab chowk in the early hours, police said, adding, that two suicidal note addressed to her mother and brother were recovered from the spot.
She has apologised to her family members for taking such step to end her life, they said.
A police-team reached the spot and recovered the body on being informed in the morning which has been sent for post mortem, police said.
The result of the CBSE board, which was scheduled to be released on Tuesday, would now be published on Wednesday.