In reality the ideal is not practiced on a wide scale. It could happen in the future and groups such as The Colours of Nature are researching possibilities. For now, eco-friendly clothing companies can choose to use plant-based dyes such as indigo, sassafras, nettles, and berries. Some chemicals are generally required to act as fixing agents and still a lot of water is used in the process.
Green clothing boutiques can also opt for dyes made from clay. Earth Creations, for example, has developed a range of beautiful colors for their clothing from clay, from jade to moonstone.
Another option is fiber-reactive dyes which are petroleum based and they do cause hazardous pollution, but they are at least better. Less water use is required and fewer heavy metals are needed. They are more expensive for the manufacturer.
For the consumer, you can look for fabrics that are made from environmentally safe dyes. Natural dyes and fiber-reactive dyes are at least a step in the right direction, although they are not entirely eco-friendly. There are also clothes that are not dyed at all, which still may have color, the browns, reds, or yellows of the natural fabrics. If you really want to go the extra mile you can always dye your own clothes using plant materials and salt or vinegar as natural fixatives.