Shopping for sustainable fashion is tricky, as it is difficult to know much about how an item has been made from the tiny amount of information that fits onto a clothing label.
However when it comes to denim, a quick glance at a pair of jeans will give you an idea of how sustainable some of the practices involved in making them were.
Which of the jeans below do you think was made using more sustainable practices?
The wash of denim holds a clue as to how sustainable some of the practices involved in making it were.
The colour blue has become synonymous with denim - to the point where you can even buy Dulux paint in the shade "denim blue".
However, denim doesn't start its life as blue. It is made from cotton, which has a natural off-white colour.
Most denim producers dye their fabric with synthetic indigo, which doesn't adhere readily to denim, so the dying process involves a lot of water and energy.
So it stands to reason that paler washes are more sustainable right?
Not so. In order to create different washes - be it sandblasted, bleached or stonewash - takes even more water and energy.
So if a pair of jeans comes with faded patches to make them look worn, then they are less sustainable than a pure indigo pair.
As an advertising campaign from the brand Patagonia states: “Denim Is Filthy Business.”
However, it doesn't have to be that way. Patagonia is on a mission to make denim production practices more sustainable.
The company has spent three years researching ways to revolutionise the production processes - and what's more they're not keeping this revelation to themselves - they're willing to share it with their competitors.
"Part of our mission statement is to use business to inspire and implement solutions to the environmental crisis," Mark Little, product line director at Patagonia told The Huffington Post UK.
"We chose not to make the process proprietary to Patagonia for this very reason. We have worked with [color and specialty chemicals company] Archroma, which developed their Advanced Denim technology.
"Beyond that, we provide information on our website and are always open to fielding queries and/or putting other companies in contact with our suppliers."
Through the research they have created a new dye process that bonds colour more readily to denim. This results in much shorter production lines that consume 84% less water, 30% less energy and emits 25% less CO2 than conventional denim dyeing.
But the wash is just one part of the story.
The synthetic chemicals used to grow conventional cotton can pollute water and air.
So Patagonia uses only 100% organic cotton grown without synthetic fertilisers, pesticides or herbicides to make their denim.
The company also has a commitment to improving factory workers’ lives, so Patagonia denim is 'Fair Trade Certified for sewing'. This means the workers involved in making the jeans receive fair compensation for their work, and money is invested in creating better working conditions and safeguarding against the use of child labour.
Other brands working towards making denim more sustainable include: Levi’s, which introduced its Water