Dewiswyd treth ar dir gwag gan y byddai hynny'n cymell datblygu mwy amserol, ac oherwydd y gallai helpu i osgoi gweld safleoedd yn dadfeilio, a hybu adfywio.
A vacant land tax has been chosen both because it could help to incentivise more timely development, and because it could help prevent dereliction and aid regeneration.