diff --git a/ddl/migrations/0218_drop_duplicate_reward_disbursement_challenge_index.sql b/ddl/migrations/0218_drop_duplicate_reward_disbursement_challenge_index.sql
new file mode 100644
index 00000000..c23047a8
--- /dev/null
+++ b/ddl/migrations/0218_drop_duplicate_reward_disbursement_challenge_index.sql
@@ -0,0 +1,5 @@
+-- sol_reward_disbursements_challenge_specifier_idx duplicates the checked-in
+-- sol_reward_disbursements_challenge_idx definition on (challenge_id, specifier).
+-- Keep the original index and remove the backfill-era duplicate.
+
+drop index concurrently if exists sol_reward_disbursements_challenge_specifier_idx;