Siebenblau is GOTS-certified for several years. The certificate is renewed each year, after criteria have been rechecked by the Control Union. You can find more information about GOTS here.
In this short clip GOTS is explained and it is made clear that using organic fiber alone is not enough but that the whole supply chain has to be considered. Correct on-product labelling is also explained in an easily understandable way:
For more information please also watch this short documentary about GOTS!