The about 20 feet by 15 feet glass door at Gate No.4 of the departure area collapsed around 9 AM, a peak hour with four different flights scheduled to leave the airport around the time, airport sources said.
A glass panel in the same area but located at an height of about 30 feet also collapsed, they said.
A boy suffered scratches caused by the falling glass pieces in the incident, the latest in a series of mishaps involving collapse of false ceiling, glass doors and cracking of granite slabs at the new terminals, built at a cost of over Rs 2,000 crore and inaugurated by Vice-President Hamid Ansari in January 2013.
On March 31, a sensor glass gate collapsed at the terminal, injuring an employee of the airport.
The international terminal is yet to be put to full use as only departures are being operated from the new one.