As noted by The Mac Observer, Apple has stopped accepting credit and debit card payments for app purchases and subscriptions made by users in India. The company’s change its policy comes to adhere to new banking laws set to take effect starting June 1, 2022.
From an Apple support page: Regulatory requirements in India apply to the processing of recurring transactions. If you hold an Indian debit or credit card and you have a subscription, these changes impact your transactions. Some transactions might be declined by banks and card issuers.
To continue enjoying your subscriptions, you can pay with your Apple ID balance. You can add to your Apple ID balance using App Store Codes, Net Banking, and UPI.