The production of raw materials is problematic. Given the large quantities of materials required by fast fashion, it is inevitable that an equally large amount of resources would be consumed.
For example, one common material used in the production of textiles is cotton. The cotton plant requires large amounts of water. For one pound of cotton, about 6400-15,500 litres of water is used. Usually, cotton crops are hydrated via irrigation instead of rainwater collection. As such, the process greatly depletes our water supply. Cotton production is an extremely large-scale process that is chemical- and water-intensive. The chemicals used such as pesticides and fertilisers are typically not absorbed by the plant. Instead, they leach into soil and water, harming the fertility of the surrounding land.
Another common material is not natural but rather, is synthetic: Polyester. Polyester is extremely popular, with nearly 21 million tonnes consumed for clothing production in 2016, a 157% increase from 2000. Polyester is made using petroleum, using up our precious little fossil fuels. Since 1975, polyester production has grown at an average of 7% per annum. This has disastrous consequences as it further depletes the fossil fuel supply, which is a Tragedy of the Commons problem.
Furthermore, 1 tonne of polyester needs an extremely large amount of electricity to produce, nearly 29,000-35,000 kWh of energy. In context, the table below shows how much 1kWh of electricity can do:
Polyester manufacturing is also a larger emitter of carbon dioxide, producing three times more than cotton. Polyester also takes extremely long to degrade. When microfibers are washed off from polyester clothing and run off into the ocean, marine environments are polluted.