World swimming's ruling body FINA has rejected 10 swimsuits, including some of those made from polyurethane and recently used in setting new world records.
The use of swimsuits in recent years has caused huge controversy in the sport because some experts, including some top swimmers, believe their use gives an unfair advantage in the pool.
FINA has reviewed all 348 swimsuits made by 21 manufacturers, and apart from the 10 rejected suits, they've called for modifications to many others.
FINA hasn't said if the world records set with the help of polyurethane swimsuits would be annulled.