Adjustment of liablity in annual return

No you cannot adjust IGST liability with missed ITC in annual report as any missed out credit of the last FY year has to be availed in the GSTR-3B of the month of September . There is no provision for availment of credit in the Annual Return. ... Hence, only those credits which have been availed in the same financial year should be considered as part of input tax credit.

You cannot adjust any liability in annual return. If there is any unclaimed ITC then it is lost. For any unpaid liability you can pay it through DRC-03