Enforce squashing while merging PRs
diff --git a/.asf.yaml b/.asf.yaml
index 8641d24..1644b0e 100644
--- a/.asf.yaml
+++ b/.asf.yaml
@@ -50,6 +50,13 @@
 
   del_branch_on_merge: true
 
+  # Enforce squashing while merging PRs.
+  # Otherwise, the git log gets polluted severely.
+  enabled_merge_buttons:
+    squash:  true
+    merge:   false
+    rebase:  false
+
   features:
     issues: true