Fabrics that are biodegradable include organic cotton, linen, hemp, bamboo, lyocell, and peace silk. Synthetic materials like nylon and polyester are not biodegradable. If a garment’s fabric is considered 99% biodegradable, then it is considered safe to compost without releasing harmful toxins. To qualify, the fabric must be organic, coloured using low-impact dyes, and even its trims (threads and buttons for example) must be compostable. Even then, clothes require an oxygen-rich environment to break down, which is why they’re not suitable for landfill.