The T-shirt is quite possibly the most universal piece of clothing. Rebellious teenager to world leader, fashion model to toddler, Mombasa to Managua, T-shirts are gender-neutral and ubiquitous and most of us own tons of them. Classic T-shirts are 100 percent cotton and we have all heard at some point that we should be buying clothing made of organic cotton, but does it really matter? Turns out, it does and here's why.

Cotton plants are thirsty

Growing cotton requires a lot of water. In fact, the production of one conventional T-shirt gulps up 2700 liters of water. Yes, you read that right, there is no decimal point missing here. And most cotton is grown in places where water is scarce. Now here's one good reason to buy organic cotton: it requires 91 percent less water than conventional cotton. So if you would like to save theAral Sea, here's your chance to do something about it.

Toxic stuff
Pesticides are very popular among cotton farmers. So much so that 25 percent of all pesticides used in the world are sprayed on cotton fields. That's despite the fact that just 2.5 percent of agricultural land is given over to cultivating the plant. Or to get back to our T-shirt: for each one made of conventional cotton, farmers dump about 150 grams of pesticides on their land. Yum! 

So think about that next time you buy a T-shirt. Or better yet, think twice about buying that new T-shirt at all. Is it really that different from the other five blue ones in your closet? 

How can I tell if it's organic?

Look for the label of the Global Organic Textile Standard (GOTS), the most widely-used certification for organic textiles. If it says GOTS and "made with organic" the shirt is made of at least 70 percent organic fibres. If it says GOTS and just "organic," the item must contain at least 95 percent certified organic fibres. Pretty good, don't you think?