diff --git a/hub/persistence/repositories/city.py b/hub/persistence/repositories/city.py
index a1459c96..20f36882 100644
--- a/hub/persistence/repositories/city.py
+++ b/hub/persistence/repositories/city.py
@@ -60,8 +60,11 @@ class City(Repository):
       for building in city.buildings:
         object_usage = ''
         for internal_zone in building.internal_zones:
-          for usage in internal_zone.usages:
-            object_usage = f'{object_usage}{usage.name}_{usage.percentage} '
+          if internal_zone is None or internal_zone.usages is None:
+            object_usage = 'Unknown'
+          else:
+            for usage in internal_zone.usages:
+              object_usage = f'{object_usage}{usage.name}_{usage.percentage} '
         object_usage = object_usage.rstrip()
         db_city_object = CityObject(db_city.id,
                                     building.name,