68 The baptismal rite should contain variants, to be used at the discretion of the local ordinary, for occasions when a very large number are to be baptized together. Moreover, a shorter rite is to be drawn up, especially for mission lands, to be used by catechists, but also by the faithful in general when there is danger of death, and neither priest nor deacon is available.
Source: Sacrosanctum Concilium (Vatican.va)