A sudden downpour led to the stampede on a Kerala campus fest that left four students dead and over 50 injured yesterday, police have said. The stampede took place ahead of singer Nikhita Gandhi's performance at an open-air auditorium at Cochin University of Science and Technology (CUSAT) yesterday. According to civic authorities and police officers, a single gate was being used for entry and exit to the open-air auditorium. The organisers were allowing entry in batches to those carrying passes. Outside the entry was a long queue of excited youngsters eager to get in. An eyewitness told the media that while entry to the concert was restricted to pass holders, many local residents had gathered outside the auditorium.