If you are unsure whether the Credit card is lost permanently or stolen, you should immediately contact the credit card department of the bank who had issued the credit card to get it blocked permanently, you can also block it temporarily if you think the credit card is only missing and you can recover it later. All major Indian banks like ICICI, HDFC, AXIS, SBI now have 24/7 phone support so you can easily block your credit card. Do note that you may have to pay some blocking/unblocking fees for the credit card.
While calling the Bank helpline numbers, they will ask you about your last transaction, if you think there are some unauthorized transactions being taken place, and then you are required to make an official police complaint so the credit card company and bank can investigate the transactions. If there are no unauthorized transactions were taken place, you can just block your card and ask for Duplicate credit card from the bank.