Question

why worlds most of the hot desert lies in western part of continent.

Answer 1

There are two major factors for western side of the continents to be relatively drier:

Trade winds are off shore in western side of the continent because it has downpoured moisture it picked from water body, on the eastern side.

[Trade winds blow from high pressure sub tropical belt(30°N and S) to low pressure equitorial belt(0°) . Because of earth’s rotation trade winds deflect towards its right in Northern hemis. And towards its left in southern hemis. Therefore you can see that it enters the continent from eastern side therefore western part receives moisture less winds. ]

Presence of cold currents on the western side of the continents causedessicating effect.

[Dessicating effect causes air to get cooled and we know that cold air— A. Carry less moisture. B. Doesn't rise(hence no condensation and subsequently no cloud formations)]

Answer 2

There are two major factors for western side of the continents to be relatively drier:

Trade winds are off shore in western side of the continent because it has downpoured moisture it picked from water body, on the eastern side.

[Trade winds blow from high pressure sub tropical belt(30°N and S) to low pressure equitorial belt(0°) . Because of earth’s rotation trade winds deflect towards its right in Northern hemis. And towards its left in southern hemis. Therefore you can see that it enters the continent from eastern side therefore western part receives moisture less winds. ]

Presence of cold currents on the western side of the continents cause dessicating effect.

[Dessicating effect causes air to get cooled and we know that cold air— A. Carry less moisture. B. Doesn't rise(hence no condensation and subsequently no cloud formations)]