Occupied by four centers, namely Ain el-Touta, Ngaous, Marana and Tazoult, with a difference in size (10137, 16767, 12083 and 5877 inhabitants) respectively, it should be noted here that Ngaous is the only center that is far from the ideal line since its actual size of 29257 inhabitants is much less than its ideal size of 46024 and given its administrative rank since it represents a district seat as well as the rest of the other centers, this means that they are suffering from a significant decrease in population size, which may be due to their proximity to the center of the state, such as Tazoult in particular and Ain el-Touta.