From Vatican Radio:
The Vatican’s Congregation for the Doctrine of the Faith on Tuesday published a new instruction on the burial of the dead and on the conservation of the ashes in cases of cremation. The instruction reiterates the long held view that the Church is not opposed to the practice of cremation, though it continues to recommend that the bodies of the deceased be buried in cemeteries or other sacred places. However the new document insists that ashes should not be kept in private houses and that the scattering of ashes on land or at sea is not permitted.
Among other things, the new document reaffirms the Church teaching on cremation:
The conservation of the ashes of the departed in a domestic residence is not permitted. Only in grave and exceptional cases dependent on cultural conditions of a localized nature, may the Ordinary, in agreement with the Episcopal Conference or the Synod of Bishops of the Oriental Churches, concede permission for the conservation of the ashes of the departed in a domestic residence. Nonetheless, the ashes may not be divided among various family members and due respect must be maintained regarding the circumstances of such a conservation.
And it concludes:
When the deceased notoriously has requested cremation and the scattering of their ashes for reasons contrary to the Christian faith, a Christian funeral must be denied to that person according to the norms of the law.
Read the full document here.