As per Section 50 of Central Goods and Service Tax Act, 2017 interest on delayed payment of GST will be applicable in the following cases as per the rates mentioned in Nofication no.13/2017 (Central Tax):

Sl. No	Description	Rate
1.	Every person who is liable to pay tax to the Govt., fails to pay with in the time period prescribed	18% on tax or any part thereof remains unpaid
2.	Taxable person claiming undue or excess claim of ITC or undue or excess reduction in output tax	24% on such undue or excess claim of ITC or reduction in output tax

The general assumption is that, the interest is payable on the net amount after adjusting the Input Tax Credit (ITC). The department had a different view on the above subject and they had issued notices stating that the interest is payable on output tax liability.

Recently the Telengana High Court in the case of Megha Engineering And Infrastructures Ltd Vs CCT also upheld the view of the department mainly on the following grounds:

1. The liability to pay interest u/s 50(1) is self imposed and also automatic without any determination by any one.
2. In terms of s.39(1) and s. 39(7), period prescribed for payment of tax in respect of every month is on or before the 20th day of the succeeding calendar month
3. Until a return is filed as self-assessed, no entitlement to credit and no actual entry of credit in the electronic credit ledger takes place. It is only after a claim is made in the return that the same gets credited in the electronic credit leger and it is only after a credit is entered in the electronic ledger that a payment could be made even though the payment is only by way of paper entries
4. If no payment is made, the mere availability of the same will not tantamount to actual payment
5. Recommendations of the GST Council in its 31st meeting that interest should be charged only on the net tax liability of the taxpayer after taking into account the admissible input tax credit as communicated in the Press Release of the Ministry of Finance are still on paper and, therefore, High Court cannot interpret section 50 of the CGST Act in the light of the proposed amendment.

Even if the Government issues notification (not issued 30-04-2019) with regard to payment of interest based on 31st meeting decision of GST Council, the applicability of that notification maybe prospective only. The assessees have to take due care and pay the interest if any applicable before filing Form GSTR 9, GSTR 9A and GSTR 9C.