Ritual Obstruction

You establish a zone of magical feedback that makes it impossible to succeed at rituals of this spell's rank or lower in the area. Ritual obstruction ignores all cover, including walls and ceilings, to the extent of its area. Anyone attempting to cast a ritual within the area knows, when they begin to cast the ritual, the area is cursed to impede rituals. Any ritual cast in the area can't have a final result better than failure.