Akash, a class XII student, allegedly fired from the toy gun when its bullet hit Ishant, who was standing on the second floor balcony of his home, said a senior police officer.
Prior to the incident, Akash was cautioned against using the toy gun by the victim in the "very cramped up" area where anybody could get hit, the officer said.
The officer said the bullet hit Ishant's eye and he was rushed to GTB Hospital from where he was referred to AIIMS. The bullet pierced through his eye and while the doctors have taken out the bullet, they will be performing an eye surgery in a few days, police said.
The victim's family later lodged a complaint with police following which Akash was booked under relevant sections of the IPC and arrested, they added.
Ishant had gone to one of his friend's house and Akash, who stays in the neighbourhood, was playing with the toy gun when the incident occurred, police said.