How do the presence of himalayas change the flow of a wind blowing from allahabad towards northern india?

A shift in the development of  low pressure trough or monsoon trough along with the seasonal change is the important reason for the change of the flow of wind blowing from Allahabad towards the northern India.

Explanation:

Himalayan mountain range are not only the physical barrier, they are also a climatic divide. The location of the Himalayas makes it favorable for the Indian subcontinent, because it obstructs the cold winds blowing from central Asia during the months of winter and circulates the southwest monsoon winds, causing it shed most of its rain inside India.  

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