A 13-year-old girl was set on fire allegedly by a boy when she resisted his attempt to sexually assault her in a village in Madhya Pradesh, a police officer said today. Police said the girl has suffered severe burn injuries and has been admitted to a hospital in Rajgarh district, 115 km from state capital Bhopal. Her condition is said to be critical as 50 per cent burn injuries is challenging for doctors to treat if infection sets in.