CCC 1483 In case of grave necessity recourse may be had to a communal celebration of reconciliation with general confession and general absolution. Grave necessity of this sort can arise when there is imminent danger of death without sufficient time for the priest or priests to hear each penitent’s confession. Grave necessity can also exist when, given the number of penitents, there are not enough confessors to hear individual confessions properly in a reasonable time, so that the penitents through no fault of their own would be deprived of sacramental grace or Holy Communion for a long time. In this case, for the absolution to be valid the faithful must have the intention of individually confessing their grave sins in the time required.1 The diocesan bishop is the judge of whether or not the conditions required for general absolution exist.2 A large gathering of the faithful on the occasion of major feasts or pilgrimages does not constitute a case of grave necessity.3

1 Cf. CIC, can. 962 #1.
2 Cf. CIC, can. 961 # 2.
3 Cf. CIC, can. 961 # 1.