celebrating

(transitive) To extol or honour in a solemn manner.
(transitive) To honour by rites, by ceremonies of joy and respect, or by refraining from ordinary business; to observe duly.
(intransitive, transitive) To engage in joyful activity in appreciation of an event.
(transitive) To perform or participate in, as a sacrament or solemn rite; to perform with appropriate rites.