Interest under section 234(b) and (c) of the income tax act

Actually department is right in levy of interest over tax relief claimed for earlier year/s.

Assessee claims that the income should be assessed in that earlier year; so department claims interest over the tax which was required to be paid in that year, but received in current year !!!

I agree but I disagree on one thing that u/s.234(b) , Interest is payable only when the Assessee failed to pay Advance Tax or where the Advance Tax paid is less than 90% of the assessed Tax. In the present cases the Relief is not more than 5% of the Assessed Tax for the respective Assessment Years. To my knowledge, Interest u/s. 234(b) & (c) was not levied in case of Relef u/s.89(1) except for the Assessment Year 2017-18. Also Relief u/s.89(1) can be claimed only when Employees were paid the arrears. It is not a fault on Salary People. The arrears arise only out of Seventh Pay Commission of the Government. Who is at fault whether the Public Sector or the poor Assessee.