Level 2 planet
From Tardis Wiki, the free Doctor Who reference
A Level 2 planet was a designation used by Galactic Law in reference to certain worlds, with the implication that it referred to relatively primitive planets. It derived from an application of socioenergetics. Other designations included Levels 1, 4, 5 and 6.
Level 2 planets included Earth, circa the 1940s, (PROSE: Ghosts of India) Trenzalore (TV: The Time of the Doctor) and the vampire planet in E-Space. (TV: State of Decay)
Few water-breathing species advanced beyond Level 2 technology. One of the exceptions included the Selachians (PROSE: The Murder Game) from the planet Ockora. (PROSE: The Final Sanction)
