What are most deserts formed near?

Most deserts are formed near the Tropic of Cancer and Tropic of Capricorn, which are located at 23.5 degrees north and south of the equator, respectively. These areas receive less precipitation than other parts of the world due to the descending air from the Hadley cells, which are part of the global atmospheric circulation. As the descending air warms and expands, it becomes drier, leading to reduced rainfall and the formation of desert conditions.