Transparent PC cover to be easily yellowed if it is NOT ANTI-UV Protection

We have a customer who, before cooperating with us, had a very regular problem with wall mounted led pool lights with PC lenses, which were also very beautiful from the outside, but the lenses were yellowing after 6-7 months of use and seriously affected the brightness of the light and the normal lighting of the pool. Finally, on our recommendation, our customer used our PC + ANTI UV led pool luminaire, and within 2 years the lenses did not yellow. This has completely solved the customer's problem and saved him about 600USD in labour costs.