Throughout the human history, disposal of the dead and the rites connected with it have acquired a religious colour for the obvious reason that death is as much an awe-inspiring wonder of nature as birth. The Hindu scriptures which look upon the whole life of a man as a yajña or a sacrifice, have treated the subject of dying, death and after-death rites as a part of religion. The rites should be conducted with proper religious fervour so that the soul of the dead gets peace.
The rite of ‘asthisañcayana’ or ‘collec-ting the bones’ (of the dead) is performed only in cases where the body has been cremated. The nearest relative of the dead person, with the help of some elders, usually old men in odd numbers, collects the charred remains of the bones in a specified way. The rite includes circumambulation of the place of cremation, sprink-ling milk with water with the branch of a śamī tree (Prosopis specigera), collection of bones from the feet to the head and filling them in an urn. Appropriate mantras from the Ṛgveda have to be chanted during the whole operation. The urn is then buried in a suitable spot, after which the relative takes a bath and performs a śrāddha or obsequial rite.
But the most common practice in the modern days is to cast the bones in the waters of holy rivers like the Gaṅgā or the sea. The Viṣṇudharmasūtras (19.11-12) approves and recommends this practice as better.
This rite is not performed for boys whose upanayana ceremony has not been performed.