Mojox was a planet under occupation by Daleks. It had a native population of over two billion Mojoxalli. Mojox had high levels of Vilonium under its surface. (AUDIO: Dalek Soul)
The Fifth Doctor and Nyssa were brought to Mojox after they were captured by Daleks on Traxana. (AUDIO: Alien Heart) They quickly escaped Mojox, but left behind enough genetic material for the Daleks to create duplicates of them. (AUDIO: Dalek Soul)