It is mandatory to carry a government issued photo identification (ID) proof along with the e-ticket copy. The same is verified by the airport security as well as the airline at the check-in counter. On presenting your photo ID proof and e-ticket copy, your boarding pass will be issued.
For international flights, your passport is the only valid photo ID proof that will be accepted. In case of an infant travelling, it is mandatory to carry the birth certificate of the infant along with the ticket. It is not mandatory to carry the credit/debit card that was used to make the payment at the time of the booking.
In case of international travel, each passenger must ensure that they carry a relevant visa, transit visa (if applicable), immigration clearance and travel with a passport, with a validity of at least 6 months as on date of travel.