We all know that Rajasthan is not completely a desert.
Only 4 districts named Jaisalmer, Barker, Bikaner, and Jodhpur out of the 33 districts come under the Thar desert of Rajasthan.
It has regions of rolling sand dunes in the west to lofty rocks in the middle to fertile plains in the east.
The main reason why the western part of Rajasthan is a desert because the Aravalli mountain range is situated parallel to the wind direction which is not obstructing the southwest monsoon wind and thereby causing no orographic rainfall. And, thus it’s a desert with lack of rainfall.
Do you know? This western desert part roughly constitutes about 70% of the total land area of Rajasthan.
There’s more information about the Thar Desert of Rajasthan. Let’s Know More
Reasons why western Rajasthan is a desert
There are various reasons to answer why the western part of Rajasthan is only a desert. Some of the well-said reasons are provided below…
Reason #1: No Moisture in the North-East Monsoon Winds
The western part of Rajasthan lies in the direction of the Trade winds. This region lies in the belt of trade winds which blow from Northeast in the Northern Hemisphere.
We can say that these winds with moisture in it after entering the India sub-continent, blows from the direction of East to West. This is the North-East Monsoon Wind.
The phenomenon is that high hills and mountains cause precipitation of the moisture in the clouds. And, we know that the Northeastern part of India is very hilly.
Thus, when the wind enters India and starts flowing it meets the high hills, mountains of the Northeastern side and so the air rises and cools.
As a result, the water vapor in the air condenses and rainfall occurs.
By the time they come to the Thar Desert in the West side of India, they had lost nearly all of their moisture causing little or no rain in the region.
Thus, Western Rajasthan is a desert.
Reason #2: The Aravalli Ranges are not blocking the South-West Monsoon winds
We know that, In India, the “Thar Desert” extends towards the southern part of Haryana, Punjab, and Northern Gujrat constituting the whole western Rajasthan.
In Rajasthan particularly, this desert is bounded by the Sutlej River in the northwest, the Aravalli mountains in the east, and the salty marshland of the Rann of Kutch in the south, and the Indus River in the west.
The landscape here we will consider is the Aravalli mountains to particularly understand this Reason #2.
Yes, you have read it right! The western part of Rajasthan is bounded by the Aravalli mountain range in the Eastside.
The Aravalli Range is a mountain range in Northwestern India, running approximately 692 km in a south-west direction, starting near Delhi, passing through southern Haryana and Rajasthan (yes Rajasthan!), and ending in Gujarat.
The highest peak is Guru Shikhar which is 1,722 metres (5,650 ft) high.
There is another type of Trade winds coming from the Indian Ocean towards the Southwest side of India.
As the wind blows from water to land, it is moist and brings a lot of rain. The wind is known as South-West Monsoon Wind.
And moreover, the Aravalli mountain in Rajasthan is situated parallel and away to the wind direction which is not obstructing the southwest monsoon wind and thereby causing no orographic rainfall.
These Aravalli ranges are not blocking the South-West Monsoon winds which carry the moisture. They are parallel to the direction of the cloud movement.
As a result, little to no rainfall occurs in the Western part of Rajasthan, thus causing the formation of a desert on the West side of the state.
Reason #3: The Epic Story of Ramayana
This reason is more of a legend story. It’s not scientifically proven but you will find it in the books of the Indian Mythology, particularly in the Epic Ramayana.
Accordingly, it is said that about 10,000 years ago, the present-day Thar Desert situated in the Western part of Rajasthan was a lush-green and fertile land.
During those days, the Sarasvati river would course through the Thar Desert on its way to the Indian Ocean.
Legends say that Lord Rama during his exile in the forest, created the Thar Desert.
It was the time when he was in search of his spouse Sita. Rama had to cross the Indian ocean from today’s Rameshwaram in Tamil Nadu, India to reach Lanka (present-day Sri Lanka).
During those days, it was not so easy to cross such a huge ocean like the Indian Ocean. So, he organized payers to make a miracle happen.
He prayed to the ocean deity for a couple of days so that the ocean water could subside and pave a way for Rama and his army to march on towards Lanka.
The deity ignored his humble prayers and didn’t even appear before Rama. This raged Rama, and he launched his powerful Archer Bow to dry up the complete ocean.
During those times, such type of incredible powers was possible as legends say.
Anticipating his end was near, the ocean deity presented himself before Rama and pleaded for mercy.
He suggested the right course to solve Rama’s problem, and since the divine weapon could not go in vain once summoned, the ocean deity requested Rama to release the weapon towards his north where a place called Drumatulya is located.
Drumatulya was the present-day Thar Desert.
Rama accepted his humble prayers and targeted his bow towards the place called Drumatulya (present-day Thar Desert) which subsequently dried up the whole Sarasvati River flowing through that region and causing the formation of a desert in the Western part of Rajasthan.
Reason #4: Drying up of the Ghaggar-Hakra River
This reason highly disregards Reason #3 of the Epic Story of Ramayana.
It shows that there was no such Sarasvati River flowing through the Thar Desert once upon a time.
In fact, it was the Ghaggar-Hakra river that once flowed through this region. The Ghaggar-Hakra River is an intermittent (temporary) river in India and Pakistan that flows only during the monsoon season.
Paleochannel pieces of evidence show the presence of this river. A palaeochannel, or paleochannel, is a remnant of an inactive river or stream channel that has been filled or buried by younger sediment.
This theory cum. reason states that the area turned to desert relatively recently, perhaps around 2000 – 1500 BC. Around this time the Ghaggar-Hakra ceased to be a major river but now, it has become an intermittent one.
It now terminates in the desert but at one time was a water source for the Indus Valley Civilization centre of Mohenjodaro.
It has been observed through remote sensing techniques that Late Quaternary climatic changes and Plate Tectonics Theory (neotectonics) have played a significant role in modifying the drainage courses in this part and a large number of palaeochannels exist showing the pieces of evidence.
Most recent studies show that both Sutlej and Yamuna rivers once flowed and connected the Ghaggar-Hakra river and thus brought lush-greenery to the present day Thar Desert.
It has been postulated that the Sutlej was the main tributary of the Ghaggar and that subsequently, the tectonic movements might have forced the Sutlej westwards, the Yamuna eastwards, and thus dried up the Ghaggar-Hakra.
And, now the river course has changed over the course of history and this had resulted in the formation of the Thar Desert in the Western part of Rajasthan.
Yes, the western part of the Rajasthan state of India is a desert that is covered by the Thar Desert of India.
This western desert part roughly constitutes about 70% of the total land area of Rajasthan.
The western Rajasthan is the only desert because the whole area covering the Thar desert is severely dry, very hot in summer, and is generally intensely poor in vegetation.
It falls under the Western Sandy plains division of Rajasthan which actually falls under the Arid and a bit of Semi-Arid Climatic Zones of India.
This desert area is characterized by very scarce natural resources and an inhospitable, extremely hot climate throughout the year.
There, rainfall varies from less than 100 mm to 400 mm and is highly erratic and unpredictable.