The Puja ceremony is carried out by the Sherpas before they go very high on the mountain. It consists of a lot of chanting, incense and then drinking and dancing. No-one works on Puja day.
It can not be under estimated the amount of work the Sherpas do for us. The loads they carry up the hill in preparation of the summit push is incredible. All the tents, sleeping bags, roll matts, stoves, oxygen, etc., etc. The speed they go up the mountain is incredible but the speed they come down is truely amazing, often runnning pushing and joking with each other while us and other westeners stagger with fatigue!