The German Wehrmacht had carried out a "scorched earth" policy, laying waste to an area "one and a half times the size of Denmark", according to Petterson.
After liberation, the local inhabitants who had evaded a German-ordered mass evacuation from the area, were allowed to move into the few buildings still standing.
First, how do you understand that grammatically? And second, what does that exactly mean? Are the buildings still in place after so many years or were they standing there after the mass evacuation?