Students at the Bhagat Pre-University College, in India, were allegedly asked to wear cardboard boxes on their heads to stop them looking at one another's exam papers.
A picture of the students was posted to Twitter and has since gone viral, forcing officials to apologise.
One official said in the apology that the cardboard box wearing was part of an experiment after hearing other schools had done the same.
"There was no compulsory aspect ... You can see in the photograph that some students are not wearing it," a staff member told BBC Hindi.