What is sustainable fashion? A clear definition, and what it asks of you

Materials & footprint · Published 2026-10-20

A short rail of shirts, jackets and coats in a bright, uncluttered shop with pendant lamps — Fewer pieces, chosen with care, is where most of the change starts. Photo: Clark Street Mercantile (Unsplash), via Wikimedia Commons, CC0.

Sustainable fashion is not a style or a label. It is the attempt to make, sell, wear and dispose of clothes in a way that the planet and the people in the supply chain can actually bear, year after year. That covers materials and factories, but also something less glamorous: how many clothes we buy, and how long we keep them.

The problem in four numbers

The clearest overview of fashion's footprint is still the Ellen MacArthur Foundation's 2017 report A New Textiles Economy. Its central findings explain why the word "sustainable" has become unavoidable:

Production roughly doubled in the fifteen years to 2015, while the average number of times a garment is worn before it stops being used fell by 36%.
Less than 1% of the material used to make clothing is recycled into new clothing. In the foundation's analysis of 2015 material flows, 73% of clothing ended up landfilled or incinerated.
1.2 billion tonnes of greenhouse gases came from textile production in 2015, more than all international flights and maritime shipping combined.
Around half a million tonnes of plastic microfibres shed by washing synthetic textiles end up in the ocean each year.

Estimates of the industry's share of global emissions vary with the method used; UN News, reporting on the International Day of Zero Waste in March 2025, put it at up to eight per cent. Whatever the exact figure, the direction is not in doubt.

Three things the word should cover

1. The environment

Every garment has a footprint before it reaches a shop: farming or synthesising the fibre, spinning, weaving or knitting, dyeing and finishing, cutting and sewing, transport. Fibre and fabric production are energy-intensive and, in places, water-intensive; dyeing and finishing discharge chemicals. A sustainable approach reduces these impacts at each stage, and above all reduces the number of new garments needed in the first place.

2. People

Clothes are still largely sewn by hand, mostly by women. The International Labour Organization estimated that in 2019 the Asia-Pacific region alone employed some 65 million garment-sector workers, about three quarters of the world's total. Fashion that underpays them, or puts them in unsafe buildings, is not sustainable in any meaningful sense. Our guide to garment workers' rights goes into the history and the laws.

3. Time

The most overlooked dimension is duration. A well-made coat worn for ten winters spreads its footprint over ten winters. The European Commission's strategy for sustainable and circular textiles, adopted in March 2022, puts it plainly: clothes should be durable, repairable and recyclable, and "fast fashion" should go out of fashion.

Linear versus circular

Most clothing today follows a straight line: extract, make, wear briefly, throw away. The circular-economy model proposes a loop instead, in which garments and their materials keep their value as long as possible. In practice, a circular wardrobe uses a hierarchy that mirrors the EU's waste rules: prevent first, then reuse, then recycle, and only then dispose.

Step	What it means for clothes	Examples
Prevent	Buy fewer new garments, choose ones built to last	Planning purchases, made-to-order, quality over quantity
Extend	Keep what you own wearable for longer	Gentle washing, stain removal, mending, alterations
Reuse	Pass garments to someone who will wear them	Resale, swaps, rental, second-hand and vintage
Remake	Turn an unwearable garment into a new one	Upcycling, deadstock fabric, reworked vintage
Recycle	Recover the fibre when nothing else is possible	Fibre-to-fibre recycling (still rare), downcycling into insulation or rags

Recycling sits near the bottom for a reason. In the Ellen MacArthur Foundation's figures, only 13% of clothing material is recycled in any way after use, and most of that is "cascaded" into lower-value uses such as insulation, wiping cloths or mattress stuffing.

Materials: helpful, but not the whole story

Much of the marketing around sustainable fashion is about materials: organic cotton, recycled polyester, certified wood-based fibres such as lyocell, linen and hemp. Better materials do matter. But a garment made from a "better" fibre and worn three times can still have a larger footprint than an ordinary one worn for years. A few practical rules hold up well:

Look for third-party certification rather than adjectives: a named standard, with a certificate number you can check, is worth more than the words "eco" or "conscious".
Prefer fabrics you can wash at low temperatures and that will survive many washes.
Be wary of blends where you cannot tell the composition; they are among the hardest textiles to recycle.
Recycled polyester made from bottles diverts plastic but still sheds microfibres, and it does not by itself close the loop for clothing.

Spotting greenwashing

Vague claims are now a legal issue in Europe. Directive (EU) 2024/825, on empowering consumers for the green transition, applies from 27 September 2026 and bans generic environmental claims such as "eco-friendly" or "green" when the trader cannot show recognised excellent environmental performance, as well as sustainability labels that are not based on a certification scheme or set by public authorities. You can use the same logic as a shopper:

Ask what exactly is better: the fibre, the dye process, the factory, the transport?
Ask how much of the product it applies to: a "recycled" jacket may contain a small percentage of recycled fibre.
Ask who checked: the brand itself, or an independent body?
Ask about people: does the brand publish its factory list and say anything concrete about wages?

Where your wardrobe fits in

Individual habits do not replace regulation, but they are not trivial either. The UK charity WRAP estimated in 2012 that around 30% of the clothing in the average British wardrobe had not been worn for at least a year, and that extending the active life of clothes by just three months per item would cut their carbon, water and waste footprints by 5 to 10% each. Those are realistic gains, available to almost anyone:

Wear what you already own more often, and shop less and more deliberately.
Look after clothes: wash cooler and less often, air-dry, and learn basic repairs. The guide to better fashion habits covers the routine.
Buy second-hand first, and pass on what you no longer wear.
When you buy new, choose fewer pieces of higher quality from makers who are transparent about how and where they produce.

The most sustainable garment is usually the one already in your wardrobe.

Sources

Ellen MacArthur Foundation (2017), A New Textiles Economy: Redesigning fashion's future, summary of findings.
UN News (27 March 2025), Fast fashion fuelling global waste crisis, UN chief warns.
International Labour Organization (2021), Moving the Needle: Gender equality and decent work in Asia's garment sector.
European Commission, EU Strategy for Sustainable and Circular Textiles (adopted 30 March 2022).
Directive (EU) 2024/825 on empowering consumers for the green transition.
WRAP (2012), Valuing our clothes: the true cost of how we design, use and dispose of clothing in the UK.