Section 18(4) of the CGST Act, 2017 requires reversal of ITC when goods or services held in stock are used for purposes that nolonger remain taxable (for example, when a person switches from regular scheme to composition, or when supplies become wholly exempt).
Now, in the context of Compensation Cess:
Cess is leviable only on notified goods (like tobacco, aerated water, coal, motor cars, etc.). If such goods subsequently go outside the purview of cess (e.g., due to amendment or exemption notification like GST-02 reforms), then the liability to pay cess on outward supply ceases from that date. However, Section 18(4) talks about “exempt supply under GST law”, not specifically about “cess”.
Once the goods remain taxable under GST (CGST + SGST/IGST), but only cess is no longer applicable, there is no requirement to reverse ITC of GST already availed. At the same time, ITC of cess component specifically availed on stock (if any) cannot be utilized once the goods are no longer subject to cess.
Such credit becomes ineligible from that date, and as per Section 17(5)/ Rule 44, proportionate reversal of cess ITC on stock in hand would be required.
Conclusion:
No reversal of GST (CGST/SGST/IGST) ITC is needed. But cess credit lying in stock must be reversed (if availed) once the goods go outside the purview of compensation cess, since there will be no output cess liability to adjust it against.
Nevertheless, some of the sin goods continue to attract Compensation Cess until effective notification for its complete removal is in place. So such of the taxpayers can utilise the balance Cess as usaual till then, if any.