/ ˈsɪvəl dəˈfens /
Or civil protection; Organized activities by the civilian population of a state to mitigate the effects of enemy attack.
During World War II civil-defense efforts were centered on providing adequate warning of air raids to permit the civilian population to reach shelter; then firefighting, food, rescue, communications, and ambulance services were needed. Subsequently, the threat of nuclear weapons led to the building of fallout shelters in the US, the USSR, and elsewhere. China has networks of tunnels in cities that are meant to enable the population to escape nuclear fallout and reach the countryside, but which do not protect against the actual blast. Sweden and Switzerland have highly developed civil-defense systems.Activities organized by civilians for their own protection in time of war or disaster.