The ruling on burial in large chambers when digging is difficult

Question:
In some countries, the ground is hard and digging in it is difficult, so large chambers are made for the dead, and a number of bodies are buried in them. When the bodies decompose, other people are buried in them again. These chambers are underground. What is the ruling on this? And is it permissible according to the Shari'ah to continue with this practice?

Answer:
If they are compelled to do so, there is no harm. There is no harm in making chambers underground or above ground that are designated for the dead, where they are placed until they decompose, and then other dead are placed in them. There is no objection to this in case of dire necessity, if there is no open land in which to bury the dead. The city is crowded and there is no open land in which to bury the dead, each dead person in a grave. In that case, these built cemeteries or these chambers are permissible, provided that the dead are respected and not insulted, and their bones are not broken.