Scream or tell someone if you are molested on a train.
With more cases of such outrage of modesty occurring on public transport last year, police want commuters to expose perpetrators as soon as possible so they can be arrested.
Last year, there were 164 reports of molestation on public transport, up from 154 in 2013, police told The Straits Times.
Overall, molestation cases increased from 1,325 to 1,367 in the same period, according to the police's annual crime statistics released yesterday.
This is still lower than the 1,420 reports made in 2012.
Arrests also went up from 781 in 2013 to 842 last year.
But more cases are occurring in public areas such as trains, parks and on the streets, said the police.
Police conduct regular patrols at train stations to deter molesters and work with transport operators to broadcast public education videos at MRT platforms on how people can protect themselves.
But commuters also have a part to play. MP Gan Thiam Poh (Pasir Ris-Punngol GRC), who is on the Government Parliamentary Committee for Transport, said: "Commuters shouldn't let their guard down and must also help each other. If you see someone taking a nap next to you, you can help to look out for them."
Mr Patrick Nathan, SMRT vice-president for corporate information and communications, advised passengers to be vigilant and victims to seek help immediately.
But many victims are too taken aback to do anything. Administrative executive Nyam Seow Wei, 25, recalled how a man on a bus touched her buttocks. "I was too shocked... so I just stared at him and walked away. Now, I try to stand closer to women instead of men."