Onsite income arrear

Hi,

I have a query regarding taxability of onsite income which is related to previous financial year.

Here is the brief summary, In FY 2018-19 there was salary recovery for extra overseas salary paid to me. The recovery was done in May 2018 by generating a payslip of Dec 2017 as below

Gross Income : X

Salary Recovery : Y

Net Salary : X-Y, which is negative

So basically, I have to payback Y amount to my company in May 2018 as part of salary Recovery and the same has been included in my taxable income.

My residential status was NRI in 2017-18.

Can I claim this onsite taxable portion as salary in FY 2017-18 and claim tax relief under it?

Thanks,

Vikas