Why does the rainfall decrease from east to the west in northern India?

(i) The northern plains receive rains from the Bay of Bengal branch of the
S.W. monsoons.
(ii) It strikes the Myanmar’s Arkan mountains and gets deflected westward
along the Himalayas.
(iii) Maximum precipitation is recorded in the north-eastern part of India
and West Bengal.
(iv) As the monsoon moves westwards, they gradually lose moisture and
rainfall decreases from east to west over the northern plains.
(v)The clouds are almost exhausted by the time they reach western
Rajasthan.