Judging by yellow enameled star this is Keibodan-related badge https://asiamedals.info/forums/keibodan-civil-defense-corps-badges.725/
Obverse
防空 - Air defense
監視 - Surveillance
air defense maneuvers badge
air defense surveillance team badge
japanese air defense badge
japanese badge
japanese civil defense badge
keibōdan
keibodan badge
防空参加記念章
防空監視章