diff --git a/fvcore/transforms/transform.py b/fvcore/transforms/transform.py
index fbe2a58..7c18f67 100644
--- a/fvcore/transforms/transform.py
+++ b/fvcore/transforms/transform.py
@@ -721,6 +721,10 @@ def apply_polygons(self, polygons: list) -> list:
             if not isinstance(cropped, geometry.collection.BaseMultipartGeometry):
                 cropped = [cropped]
             # one polygon may be cropped to multiple ones
+            if isinstance(cropped, geometry.MultiPolygon) or isinstance(
+                cropped, geometry.GeometryCollection
+            ):
+                cropped = cropped.geoms
             for poly in cropped:
                 # It could produce lower dimensional objects like lines or
                 # points, which we want to ignore