What does selective service 1Y classification mean?

Registrant available for military service, but qualified only in case of war or national emergency. Usually given to registrants with medical conditions that were limiting but not disabling (examples: high blood pressure, mild muscular or skeletal injuries or disorders, skin disorders, severe Allergies, etc.). Class was discontinued in December, 1971 and some members were reclassified as 4-F,Others 1-H,etc.