Whenever my colleagues are in a group conversation, they talk about world affairs and finance, and politics. What should I do if I always have nothing to contribute to the discussion?

Asking questions and listening intently are great suggestions.

Well, since you pointed out finance, I will just share that I am not the most interested in investing as I think that life should sometimes just be savored instead of strategising about getting more money. Nevertheless, I feel this lack of investing knowledge, so I always like to ask my friends, "what is your investment habit like?" / "so does this piece of news affect the way you invest?"

I ask these questions so that I will become genuinely interested in their answers. and sometimes, i derive interesting nuggets of financial information that I want to act upon.

Be yourself. No point spending time reading up and ended up not understanding and not remembering them. Just join in the conversation, listen to what they share and ask them if you do not understand.

Sometimes these discussions may just be gossips and may be of no value to anyone whatsoever, so take it with a pinch of salt while trying to read up more yourself from credible sources.

Like you, I was not one who liked keeping up with the news but I knew the importance of it. Honestly, it can't be forced and you must have the interest in it otherwise it will be difficult for you to consistently keep up with it.

I started off with only reading the headlines. You will be surprise how much you can discuss about with just the headlines. Subsequently, I started reading the contents of the headlines which I felt was interesting. Just like that, I slowly natured my love for reading news. I would recommend you to try out Google News as I really like the user experience.