I am half Syrian, but I haven’t personally experienced very severe discrimination or harassment on public transport. I get some stares and nasty looks when I’m wearing a dress.
I have witnessed a few incidents of discrimination or harassment. The latest one is fresh in my memory: I was on the metro with my friends, when a middle aged man entered. He sat on a seat opposite a female passenger and started shouting at and berating her. He yelled that women always take up space on the metro, swore, and called her names. None of the other passengers reacted, and everyone looked away. My friends and I thought about what to do. The woman changed seats and moved further away from the harasser. I tried to let her know with a look that I support her, and at the same time check how she was doing. When we were getting off the metro, I asked her if she was alright.
The most important thing during incidents of discrimination or harassment is to support the victim. It is also the safest thing to do – a small gesture is enough. For example with a kind look you can send the message that I am on your side.