Why does the state of Rajasthan receive very little rainfall compared to many other parts of India?

Introduction / Context:
Rajasthan contains the Thar Desert, one of the driest regions of India, and understanding why it receives so little rainfall is an important part of Indian climatology and regional geography. This question asks you to identify the main reason for Rajasthan's low rainfall, focusing on how monsoon winds behave when they cross this region.

Given Data / Assumptions:

• The options suggest explanations based on temperature, lack of water, failure of monsoon and absence of a barrier.
• We are concerned with the south west monsoon winds that bring most of India's summer rainfall.
• We assume the typical monsoon pattern in which moisture laden winds rise and cool when forced over mountain barriers, producing heavy rain on windward slopes.
• Rajasthan lies in the leeward side of the Aravalli Range relative to the main path of monsoon currents.

Concept / Approach:
Rainfall is closely linked to uplift and cooling of moist air. When moist monsoon winds encounter a mountain barrier perpendicular to their direction of movement, they rise, cool and condense, leading to orographic rainfall. In Rajasthan, the Aravalli Range runs roughly parallel to the general direction of the advancing monsoon winds instead of across their path. As a result, the winds are not forced to rise significantly over this range and pass through largely without shedding much moisture.

Step-by-Step Solution:
Step 1: Recall that the south west monsoon winds that reach north western India travel broadly from the Arabian Sea towards the north east.Step 2: Observe that the Aravalli Range in Rajasthan runs in a north east south west direction, nearly parallel to the incoming monsoon winds rather than across them.Step 3: Because the winds and the range are almost aligned, the air is not forced sharply upward, so uplift and cooling are limited and very little orographic rainfall occurs over Rajasthan.Step 4: Therefore, the key reason for low rainfall is that the winds do not encounter an effective mountain barrier to cause the necessary uplift and cooling.

Verification / Alternative check:
Regional climate descriptions in geography texts emphasise the parallel alignment of the Aravalli Range and the monsoon track. Maps showing rainfall distribution clearly highlight a sharp decrease in rainfall from the Western Ghats towards the interior parts of Rajasthan. This spatial pattern supports the explanation that topography and the lack of suitable barriers, rather than temperature alone, determine the dryness of the region.

Why Other Options Are Wrong:
It is too hot is incomplete and misleading because many hot regions elsewhere still receive plenty of rainfall when moist air is forced to rise. There is no water available so the winds remain dry is incorrect because the Arabian Sea branch of the monsoon is already moisture laden when it reaches the western coast and inland regions. The monsoon winds fail completely to reach the region is also wrong, since some monsoon currents do pass through Rajasthan, but they do not produce much rain because they lack sufficient uplift.

Common Pitfalls:
Many learners oversimplify by linking high temperature directly to low rainfall, forgetting that deserts can be cold as well and that rainfall is more about uplift and moisture. Others may believe that the monsoon simply stops before reaching Rajasthan, ignoring the direction and behaviour of the winds. Studying a map that shows both the path of monsoon winds and the orientation of the Aravalli Range can greatly reduce such misunderstandings.

Final Answer:
Rajasthan receives very little rain mainly because the monsoon winds do not come across any significant mountain barrier there to rise, cool and give rainfall.