ITC Reversal of 2017-18

According to me first, wait for an annual return of F.Y. 2017-18 

If any adjustment Table than adjust in annual return 

You can reverse the excess ITC by reporting the same under GSTR-3B > Table 4 > Section B (ITC Reversed)

If it pertains to anything other than Rule 42 & 43 of CGST/SGST Act, then report it in "(2) Others".
(for, e.g. excess ITC on inward supplies, excess ITC reported and c/f through TRAN-1, ITC related to inward supplies unpaid for more than 180 days, etc.)

Calculate and add interest on the same in Table 5.1 of GSTR-3B.

Even though the ITC pertains to FY 2017-18, you can still report the same in current period. Some taxpayers have received notices w.r.t. short reporting of Tax Liability / Excess Credit of ITC for FY 17-18 and were advised to pay the same /utilise the credit by reporting it in current 3B returns.

I Agree to Mr. Shailendra. Further delay in reporting will simply increase your interest liability.

Yes you can reverse the ITC credit wrongly availed with interest.