Abstract: A multi-layer woven or knitted fabric exhibiting reversibly changeable air permeability, which contains reversibly crimping cellulose acetate fibers exhibiting a percentage of crimp of less than 10% at a humidity of 95% or above and a percentage of crimp of 20% or above at a humidity of 45% or below and which has a basis weight of 100 to 350 g/m2. When water content of the fabric is enhanced by the absorption of water or moisture, the air permeability of the fabric increases to inhibit in-clothes stuffiness or stickiness due to sweat and in-clothes temperature rise, while when the fabric has discharged the water into the outside environment, the air permeability of the fabric decreases to the original one to prevent the body temperature from lowering excessively because of the heat of vaporization and thus keep the in-clothes environment comfortable.

Abstract: A multi-layer woven or knitted fabric exhibiting reversibly changeable air permeability, which contains reversibly crimping cellulose acetate fibers exhibiting a percentage of crimp of less than 10% at a humidity of 95% or above and a percentage of crimp of 20% or above at a humidity of 45% or below and which has a basis weight of 100 to 350 g/m2. When water content of the fabric is enhanced by the absorption of water or moisture, the air permeability of the fabric increases to inhibit in-clothes stuffiness or stickiness due to sweat and in-clothes temperature rise, while when the fabric has discharged the water into the outside environment, the air permeability of the fabric decreases to the original one to prevent the body temperature from lowering excessively because of the heat of vaporization and thus keep the in-clothes environment comfortable.