The antarpat is an opaque cloth, usually a dupatta or shawl, used as part of a Hindu wedding ceremony. Akin to the veil worn by a bride in a Western wedding ceremony, the antarpat is held between the bride and groom as the bride walks down the aisle, so neither the bride nor the groom can see each other during the processional.
As the bride approaches the groom, the people holding the antarpat will pivot so the bride and groom don’t catch a glimpse of one another. The bride and groom then stand on opposite sides of the antarpat as the priest begins the wedding, eagerly awaiting their first glimpse of one another on their wedding day. At the designated moment, the priest will ask for the antarpat to be lowered, and the bride and groom will see each other for the first time.
Who holds the antarpat? It depends. Most of the time we see male relatives of the bride and groom playing this role, probably because (1) it’s hard to hold the antarpat for the entire processional and (2) you need tall people to hold the antarpat at a level that blocks both the bride and groom from being able to see one another. If you have a brother or cousin you’d like to include in your wedding somehow, this is a nice way to honor them.
Like most things in Hindu weddings, this is an optional addition to the ceremony. It is more common in modern weddings as a way to inject some fun and drama into the occasion, especially as brides and grooms are less frequently covering their faces during the wedding ceremony and could therefore easily see one another without this handy screen.