Question

why the annual precipitation varies from over the rest over 400cm in meghalaya to less than in ladakh and western Rajasthan

Answer 1

1)  Precipitation is mostly in the form of snowfall in upper parts of Himalayas while it rains over the rest of country.
2)  Hence, the annual precipitation varies from over 400 cm in Meghalaya to less than 10cm in Ladakh and western Rajasthan.
3)  This is the reason for low rainfall in Ladakh and it snows in this region. 

Answer 2

due to its climate and

its a greenery placf