This is my shopping bag, and I love it. It’s strong, it’s colourful, it’s washable and it’s large enough to carry enough groceries to make a tasty dinner. But that’s not why I love it so much – I love it because it could just be the world’s most sustainable bag.

Supermarkets sell “green” bags. You know – the extra heavy-duty large plastic “bags-for-life” that they sell at the till, and replace when they are worn out. But they use a lot of plastic, and need to be mass-produced. And they wear out – suggesting that the “bag-for-life” is somewhat misleading advertising.

And then there are those fashionable canvas and nylon bags that scrunch up to fit inside your handbag, with cute designs and “I’m not a plastic bag!” slogans. But these are still items that need manufacturing, shipping, printing, producing from raw materials…

This shopping bag is different. It doesn’t just stop me using new plastic bags – it’s made from old ones. It’s been upcycled. Around 80 discarded bags were saved from being dumped. The bags were thoroughly washed, then cut into thin strips, which were then knitted like yarn to produce my bag. But that’s not all. This bag was made in on Costa Rica’s Caribbean coast. Waste disposal and recycling facilities are rare in this region, so much of the trash ends up floating out to sea or polluting the beaches and rainforests. Endangered sea turtles live off the Costa Rican coast, and just they love to eat jellyfish. Unfortunately, a floating plastic bag can resemble a tasty jellyfish – and a turtle who munches on one of these will end up with more than just a little indigestion; they will die. These bags literally kill.

But my shopping bag’s story gets better. These once-deadly bags were gathered, cleaned, sliced and knitted by local women, earning them a nice little income in a region with few employment opportunities – particularly for women. The bag project has also been carried out along the Caribbean coasts of neighbouring Panama and Nicaragua, meaning fewer sick sea turtles, fewer polluted beachs, and more empowered women. In 2007, over 50,000 plastic bags were collected, and $20,000 was earned in sales, 20% of which went straight back to those awesome women.

So that’s why I love my bag.