Kolpasha was a planet.
When Gary Rudge maligned his clothing, the Sixth Doctor said that it was the height of fashion on Kolpasha. (PROSE: Instruments of Darkness) He also told Evelyn Smythe that he got his clothes there (AUDIO: Real Time). Some time after that, he took Melanie Bush to Kolpasha, where she bought an outfit that she wore several weeks later on Carsus. (PROSE: Spiral Scratch)