I may be wrong, but "Hacker News" does not appear to be trademarked in the US. And the code is open source. So which particular laws are being broken here?
It also occurred to me that hackernews.in is clearly a website aimed at Indians, so I don't know to what extent US law applies.
Anyway, it seems that the name is going to be changed, so this whole trademark point becomes moot. http://hackernews.in/item?id=375