The formation of the African and Eurasian desert belt can be primarily attributed to the location of these areas in the sub-tropical high pressure cells. These cells are characterized by sinking air masses, which suppress cloud formation and precipitation, resulting in arid conditions. Additionally, the desert belt is also affected by other factors such as the rain shadow effect caused by the high mountains, which block the passage of moisture-laden clouds and prevent rainfall on the leeward side. Warm ocean currents may also have some influence on the formation of desert regions but it is a secondary factor.