"On many occasions I had to face this kind of abuses. Most helpers try to touch female passengers' body when they get on or get off a bus," said Rima. "When women travel standing in a crowded bus, some passengers also do it."

"The way girls are abused can hardly be noticed by other passengers travelling in the bus. Only the victim can realise it. The victims can't protest as in most cases they can't identify who in the crowd is the culprit," Rimi said.

"Once I protested such act by a bus helper, but nobody came to help me. Moreover, I found it embarrassing to explain the incident to male passengers."

Rimi said after the bitter experience, she started coming to college by auto-rickshaw, which is difficult for her to afford daily.

Advocate Salma Ali, executive director, Bangladesh National Women Lawyers' Association (BNWLA), said it is very difficult to prove such offence although it is punishable under the Bangladesh Penal Code.

"The existing law is not adequate to punish the culprits, it needs amendment," she said adding that there is no clear definition of sexual abuse and physical abuse. So there are always confusions about the nature of such crime.

This correspondent asked several bus conductors what they do when any female passenger complains about such abuse against any male passenger. "I just rebuke him but can't drop him," said Ramjan, a conductor.

"What shall I do? I have nothing to do in this regard," said another conductor. He however said such incidents are rare in his bus.

"It is a common phenomenon that the victims do not raise their voice against the abuser. They do not want to be embarrassed before others," said Dr Mahmudur Rahman, professor at the Department of Clinical Psychology, Dhaka University.

"These people are either mentally sick or criminal," he said adding that social awareness and change of mindset are needed to check such abuse. If other passengers come to help the victims, the number of such incidents will definitely decline.

Some passengers said the bus owners can put stickers inside the bus to create awareness asking the passengers to behave gently with women. Such stickers will work as a warning for the prospective abusers, Mahmudur said.