Pa dystiolaeth wnaeth Llywodraeth Cymru ei defnyddio wrth ystyried terfyn cyflymder 50mya?
Wedi'i ateb gan Y Dirprwy Weinidog Newid Hinsawdd | Wedi'i ateb ar 23/11/2022
Information regarding the use of the 50mph limit for Air Quality can be found in the following links 50mph speed limits to reduce pollution | GOV.WALES which contains this link to the 5 individual WelTAG stage 3 studies Tackling roadside nitrogen dioxide concentrations in Wales (WelTAG stage 3) | GOV.WALES