Thirty-seven students narrowly escaped a tragedy when a bus in which they were travelling caught fire here on Tuesday, officials said.The private bus caught fire while heading from Delhi Cantonment to south Delhi. It was carrying the students of Kendriya Vidyalaya's Naraina branch when the incident occurred near Dhaula Kuan, a fire official said.None of the students suffered any injuries as bystanders came to their rescue. "People alerted the driver and called the police... The bus was stopped and the children were evacuated safely before the fire brigade reached," he added.Three fire tenders doused the flames but by then the vehicle was gutted. The reason for the fire is yet to be ascertained.