The 31-year-old man, a taxi driver, attacked the woman when she was returning from college on December 16.
The woman was admitted to the All India Institute of Medical Sciences here Monday with 70-80 per cent burns, Rishikesh Medical Superintendent Dr Brahma Prakash said. She was sent in an air ambulance to Delhi this afternoon, he said.
The man had been staking her after she had rejected his love proposals, police said, adding that he set her on fire after sprinkling petrol over her. After hearing her cries for help, locals rushed to the spot and took her to the hospital.
Angry students of her university were demanding capital punishment for the accused who was arrested on the same day the crime was committed.
(With inputs from agencies.)