I checked the claim that fast fashion causes a lot of pollution, and it is mostly true. A study in Nature says the fashion industry makes about 92 million tonnes of waste every year, uses a lot of water, produces toxic wastewater, and creates a lot of CO2. Other sources, like the United Nations Environment Programme and the World Bank, also say textile production pollutes water and uses many resources. Some sources focus on environmental problems, so they may emphasize negatives. Evidence supporting the claim includes waste, water use, and CO2 emissions, while some data includes the whole fashion industry, not just fast fashion. I didn’t contact the original poster, but the sources are trustworthy and show the claim is mostly correct.