Income tax for arrears

I am a senior citizen (65)

I was sanctioned a monthly pension of Rs 50,000/= from 01/04/2018

This was paid from July 2019 with arrears from the former date and continue to be paid
The DDO is deducting income Tax for the entire amount as if the pension pertains to this year only
though it pertains to previous financial year also
can I save tax and to what extent and how
I have no other income