"报上社会新闻" can be translated into English as "report social news in the newspaper" or more naturally as "cover social news in the newspaper".
Here, "report" or "cover" both convey the meaning of presenting or discussing news, while "social news" refers to news related to society or social issues. The phrase "in the newspaper" specifies the medium where this news is reported.
If you're looking for a more concise or idiomatic expression, you might also say something like "The newspaper features social news" or "Social news is covered in the newspaper", depending on the context and emphasis you want to convey.