At the time of the First Doctor's visit to the planet, the city dated back from before the Thousand Year War. The Daleks lived not in the city itself, but rather below it where they thought they were shielded from radiation.
The entire city ran on static electricity transmitted through metal floors, which the Daleks of this era of Skaro history required to power their casings. As a consequence of this dependence, the Daleks were unable to leave their city. They were unaware that a group of Thals had also survived the neutronic war.
During the war between the Humanised Daleks and the Daleks ruled by the Emperor Dalek, the Daleks had a city which the Second Doctor, having visited before, knew how to navigate. Fighting between the two groups of Daleks devastated the city ending the Great War. (TV: The Evil of the Daleks, PROSE: The Evil of the Daleks)
After the Civil War, the Daleks rebuilt the Dalek City and introduced a new command structure involving Gold Daleks which outranked the Black Daleks. (TV: Day of the Daleks, TV: Frontier in Space, PROSE: Day of the Daleks)
Behind the scenes Edit
The Dalek Handbook states that the city was named Kaalann. Dialogue in the video game City of the Daleks suggests that this city is the same as the Kaalann in the game, when the Eleventh Doctor says of Kaalann, "Last time I saw it, it was in ruins and the Daleks had fled".