What features of the nature of Algeria determine the low population density in a significant part of its territory?

Algeria is located in the region of North Africa, most of which is occupied by the Sahara wasteland with a hot and dry climate. The entire southern and central part of Algeria (about 80% of the area) is covered with deserts. Due to the lack of drinking water, large settlements are not being built in the desert part of the country. Most of the population lives in the north of the country, where the climate becomes more suitable for human life, since it is located on the seashore and is separated from the desert by the Atlas mountain system.