diff --git a/src/blackboard/db.py b/src/blackboard/db.py
index a8ebe5b..245f968 100644
--- a/src/blackboard/db.py
+++ b/src/blackboard/db.py
@@ -232,7 +232,6 @@ _SCHEMA_STATEMENTS = [
     "CREATE INDEX IF NOT EXISTS idx_tasks_status ON tasks(status)",
     "CREATE INDEX IF NOT EXISTS idx_tasks_assignee ON tasks(assignee)",
     "CREATE INDEX IF NOT EXISTS idx_tasks_parent ON tasks(parent_task)",
-    "CREATE INDEX IF NOT EXISTS idx_tasks_card ON tasks(card_id)",
 
     # comments
     """CREATE TABLE IF NOT EXISTS comments (