In light of this article what are the possible problems with burying the deceased in underground crypts?
The article mentions:
The head of the Jerusalem burial society told Haaretz that there is no Jewish legal restriction barring burial in such tunnels, making it permissible to Orthodox groups that question the validity of burial in Israel’s multi-story tombs.
Another article mentions that our current practice was actually adopted from the surrounding countries:
This was the customary way for Jews in the Land of Israel to bury their dead during Talmudic times, some 1,500 years ago.
The idea is being floated by Rabbi Rafael Ostroff, Chairman of the Etzion Bloc Religious Council.
He told IDF Radio Monday: "At this time, burials are being conducted in ways that were not practiced in the Land of Israel during the time of the Mishna and Talmud. Rather, it seems that we learned this from the countries we were in during the period of exile.
"Now that we have returned to the Land, one of the burial options is something called 'likud atzamot' (literally – 'the collecting of bones'). A person is buried, as is done today, in a regular grave, and a year later, the bones that remain are collected and placed in an ossuary."
What are the halachic issues concerning such burial practices in this day and age?