"When the bus reached Muradnagar area the three youths suddenly started molesting the girl. After some time, the girl mustered courage and slapped one of the youths," a senior police said.
One of the accused, who was carrying petrol in a bottle, poured it on her and tried to set her ablaze, the officer said.
However, the bus passengers overpowered the youths. Later, two accused gave a slip to the crowd while one of them was handed over to police.