The city contains a monument that generates +2 culture. However, the net Culture says zero. The tooltip for Culture +0 says "-2 from policies". What policy causes the -2?
This city was originally Ghandi's capital. It was taken over by Ashurbanipal. He offered it to me to induce peace. I annexed it and purchased a Courthouse.
If I purchase a Pagota, which provides +2 culture, the city produces a net +2. Whatever effect is applying the -2 seems to be a flat -2.