Question

Why most of the world's desert are situated in the western margins of continents in the subtropics​

Answer 1

Most of the worlds deserts are located in the western margins of continents in the subtropics because the prevailing winds in the tropics are tropical easterly winds. The tropical easterly winds become dry by the time they reach the western margins of the continents and so they bring no rainfall.

Answer 2

Answer:

We observe that most of the deserts are on the western sides of the continents in the subtropics. These are the results of the prevailing easterly winds of the tropics, which are the trade winds. ... These winds become dry when they reach the western sides of the continents, and hence don't bring any rain with them