noun
air defense
Military and civil protection against aerial attack. Common in compounds like 防空壕 (air-raid shelter) and 防空演習 (air-defense drill).
第二次世界大戦中、多くの都市で防空壕が使われた。
During World War II, air-raid shelters were used in many cities.
政
The government announced the strengthening of air defense systems.