Cases of coronavirus have risen sharply to their highest ever levels as the Omicron wave has surged across Wales in the post-Christmas period.
Mae achosion o’r coronafeirws wedi codi'n sydyn i'w lefelau uchaf erioed wrth i'r don Omicron gynyddu ledled Cymru yn ystod y cyfnod ar ôl y Nadolig.