A teenaged Class 8 student of a private school was in a critical condition after he set himself on fire in the school premises Wednesday in this Haryana town adjoining Delhi, police said.The student was rushed to a local hospital here from where he was referred to Delhi's Safdarjang Hospital for treatment.Police said the student received 40 percent burn injuries. Preliminary investigations revealed the student brought petrol in a bottle in his school bag, poured the petrol on himself in a bathroom after the school assembly and set himself on fire.The reason for his action is not clear yet, police said.School staff and faculty poured water on the burning child to douse the flames.Police officials said that school authorities were being asked about the student and the probable reasons why he tried to burn himself.