Time Out says
La Taronjada (loosely, The Orange Festival) consists of an innocent 'battle' between the Carnival players and the public of orange balloons and confetti, recalling the actual oranges that were once thrown. Even though it's one of the oldest traditions of Barcelona's Carnival celebrations, La Taronjada has established itself in recent years as one of the central events of the festival in the city, turning the Ribera district into the epicentre of the Carnival festival. It consists of four parts:
4.30pm: Popular Culture and Traditional Catalan Carnival Dances (Plaça Comercial).
6.15pm: The Battle of La Taronjada (Plaça Comercial).
6.30pm: The Carnival La Taronjada Soirée: Masquerade Dance (Plaça Comercial).