Every January 9, the Traslación of the Black Nazarene (commemorating the "solemn transfer" of the image's copy from San Nicolás de Tolentino in Intramuros to Quiapo) makes its way along the streets of Quiapo, with attendees reaching up to 12 million. In recent years a persistent misconception has the Traslación being repeatedly referred to (by the media as well as unscrupulous politicians) as mostly the "Feast of the Black Nazarene" (Pistá ng Itím na Nazareno), and sometimes the "Feast of Quiapo" (Pistá ng Quiapo), which despite the chaotic yet festive atmosphere are far from correct: the Black Nazarene's liturgical commemoration is on Good Friday(the second date of the year on which the image is processed). The basilica's parochial feast day, meanwhile, is on June 24 (concurrent with Manila Day) – the birthday of its titular, John the Baptist.
In recent years, the processional route was altered due to a rise in accidents, to afford other neighbourhoods off the traditional route a chance to participate, and because of structural deficiencies in nearby bridges. It is normally only a school holiday for the schools near the processional route, but for the first time in the city's history, Mayor of ManilaJoseph Estrada in 2014 declared the day a special non-working holiday due to the impassability of some thoroughfares and projected congestion in others.
~ Source: Wikipedia
