These challenges will also be considered further as part of the 4-year review which is now well underway, including as part of the assessment of alternative measures proposals.
Bydd yr heriau hyn hefyd yn cael eu hystyried ymhellach fel rhan o'r adolygiad 4 blynedd sydd bellach yn mynd rhagddo, gan gynnwys fel rhan o'r asesiad o gynigion ar gyfer mesurau amgen.