Solution

One of the most important ways in which the Himalayas influence the Indian climate is by trapping the monsoon winds, forcing them to shed their moisture within the subcontinent.  Had there been no Himalayas, the South Western monsoon winds would have had an almost uninterrupted passage over the Indian mainland. This would leave little scope for any kind of orographic rainfall over the Indian subcontinent.  Thus, the Long Period Average value of the rainfall recorded in India would be lower than the present value (89cm) as other mountain ranges (Western Ghats, Satpuras and the Vindhyas) would still cause some, if not much, orographic rainfall.