In an alternate universe, the Purple Areas of Rutan Space was the term given to a region of space belonging to the Rutan species. It was the home of their races biological warfare programme where they devastated the area with the native species being sacrificed in the quest to develop the ultimate virus to be used against the Sontarans.
As a result of the Rutans actions, the Sontaran Empire deployed forces for training on the planet Holfactur that was situated within the Purple Areas of Rutan Space. This provoked a Rutan response where they raided and devastated the site which the Sontarans claimed was the source of the Sontaran-Rutan War. (PROSE: The Infinity Doctors)