Unlike annual Shradh, Asthi Visarjan in the holy Ganga at Kashi can be performed on any day and at almost any time during daylight hours. The act itself is supremely purifying.
It is generally advised to perform the immersion without unnecessary delay after the ashes are collected.
While any day is good, performing it during religiously significant periods like Pitru Paksha, Ekadashi, Purnima, or Amavasya might be considered to add further merit, but waiting is not required. Avoid performing the immersion after sunset.
