What Fuels Fashion?’ is a special edition report of the Global Fashion Transparency Index. It has been designed to measure transparency of brand disclosure about climate and energy-related data in their own operations and supply chains. The research is broken down into five key themes, including: Accountability, Decarbonisation, Energy Procurement, Financing Decarbonisation and Just Transition and Advocacy. 

200 of the world's largest fashion brands have been selected based on their annual turnover, over $1 billion USD and representing a spread of market segments including high street, luxury, sportswear, accessories, footwear and denim from across Europe, North America, South America, Asia and Africa. Where brands are privately held, estimates have been made regarding their size and turnover. Geographic spread is considered too.

The 2024 and 2025 methodologies has been designed by the Fashion Revolution team with consultative input from a committee of experts including New Climate Institute, Stand.Earth, Action Speaks Louder, Transformers Foundation, Planet Tracker, CDP, InfluenceMap, EnergyTag, Peter Ford and Illishio Lovejoy (Laudes Foundation) among others. This research is funded by the Laudes Foundation, Pooled Fund on International Energy and Tara Climate Foundation.