"Mae gweithredu'r terfynau cyflymder 50mya, am resymau amgylcheddol, ar rai o ffyrdd prysuraf Cymru yn fater pwysig i fynd i'r afael â llygredd ac i roi dyfodol glanach ac iachach i Gymru a'i chymunedau.
“The implementation of the 50mph speed limits, for environmental reasons, on some of Wales’s busiest roads is an important issue to tackle pollution and to give Wales and its communities a cleaner and healthier future.