he now had to adjust short or excess Liability and ITC in GSTR-3B of subsequent month, accordingly in april month, he has to enter Tax Liability in CGST-SGST column short by 50,000 each and add the 1,00,000 extra in cess column. for ITC, he has to enter 40,000 each short in CGST-SGST column and 80,000 extra in Cess column. 

@Afshaan Javed
Sir, actually the error was of march 2017 and it is now Apr 19…and also now monthly liability of CGST is around 25000.
If i adjust it in GSTR-3b, I need to show atleast 3 months return with 0 outward liabiliy (As it is not possible to show negative figures in GSTR-3b).
Also, how will i give effect of correction made in Apr 19 of Mar 17 in Annual return of FY 2017-18

Dear, the corrections of FY 2017-18 can be done till due date of GSTR-3B of March 2019 i.e., 20th April,2019 vide order no.2 of FY 2018 dated 31st December, 2018. coming to your 2nd part of Query, monthly Liability is Rs.25,000 under CGST, same with SGST, u need to show 2months Liability under these heads as Nil as negative figures can be entered in GSTR-3B. Last remedy for this is that you have to report rs. 25,000 Liability in earlier month, say Sep. or Oct. 2018 or any previous month and remaining 25,000 in March, 2019 return and the short 25,000 of Sep/oct/any other month of 2018 can be adjusted till sep.2019 Return. For reporting in Annual return of FY 2017-18. there is a column which requires to report the Liability or ITC  of FY 2017-18 declared in April to Sep 2018 return, but the corrections of FY 2017-18 can be done till March, 2019, which requires amendment in Annual return of FY 2017-18. as the last date of Annual return is 30th June,2019 till then let’s hope that the required amendment may be done.