Wartime production during World War II required vast amounts of cotton, silk, nylon, wool, leather, and rubber. In 1942, the United States War Production Board issued Regulation L-85, cutting the use of natural fibers in clothing and mandating a 10% reduction in the amount of fabric in women's beachwear. To comply with the regulations, swimsuit manufacturers removed skirt panels and other attachments, while increasing production of the two-piece swimsuit with bare midriffs. At the same time, demand for all swimwear declined as there was not much interest in going to the beach, especially in Europe.