Colony 34 was one of 49 colonies in a binary star system.
After being settled, it was realised by the government that there were fewer natural resources than originally thought. With energy in short supply, public confidence in the government declined. To maintain control, they staged fake terrorist attacks and other distractions to postpone new elections.
Eventually, it was realised that people could be used as fuel, so the government encouraged immigration to increase the supply of potential bodies for that purpose. The truth of what was happening was finally revealed by the Seventh Doctor, Ace and Hex. (LIVE 34)