Name That Magic Site

[Edi]

Yes, it does, far worse than the VoIH. IIRC those two are the only purely negative ones.

Almost any of the disease sites (Inkpot End, Chillsick Swamp, Leper Fens, Plaguewater Stream, Pool of Unhealthy Rites and Crown of Darkness) make provinces unusable unless you have lots of undead or demons. Or expendable mages. Leper Fens and Crown of Darkness are worst, with 10% disease (Crown has 40% Thaumaturgy bonus), Chillsick Swamp and Inkpot End have 5% disease and the other two are 3%.

A couple of other sites that one generally doesn't want in the vicinity are The Valley of Shame (1N, increases Sloth and Turmoil) and Desert (increases Heat and Death, nothing else, but needs to be scripted).