 In 2017, New York City began removing the yellow signs since members of the public are unlikely to find viable food and medicine inside those rooms.Similar projects have been undertaken in Finland, which requires all buildings with area over 600 m² to have an NBC (nuclear-biological-chemical) shelter, and Norway, which requires all buildings with an area over 1000 m² to have a shelter.The former Soviet Union and other Eastern Bloc countries often designed their underground mass-transit and subway tunnels to serve as bomb and fallout shelters in the event of an attack.