Mae clystyrau o achosion positif wedi’u hadrodd yng Nghymru sy’n deillio o bobl sydd wedi dychwelyd o’u gwyliau, ond heb hunanynysu am 14 diwrnod yn ôl y gofyn.
Clusters of positive cases have been reported in Wales stemming from people returning from holidays who did not self-isolate for 14-days as required.