The Dutch magazine Libelle has done some research in cooperation with the Textile Museum in Tilburg. The answer? The quality of the thread is to blame. A t-shirt is usually made from single jersey, i.e. a fabric with a single thread. If one of these thin threads breaks, it immediately leaves a hole in the fabric.
T-shirts made with two threads don’t develop holes as easily, but because this type of fabric is more expensive, many apparel manufacturers choose to work with just a single thread. Holes that form around the belly button are likely caused by a belt buckle or other sharp edges such as on a table or countertop. So be careful here! Holes in clothing are nothing new for many, according to Dutch TV show Radar, which has been investigating the matter. This sparked a wildfire of reactions, as even the experts polled blamed the quality of the clothes as a result of “fast fashion”.