This puts them on an uneven playing field with commercial competitors, an issue which was acutely highlighted during the COVID-19 pandemic, and which prevents investment in zero emission buses.
Mae hyn yn eu rhoi o dan anfantais pan fyddant yn cystadlu â chwmnïau masnachol, mater a amlygwyd yn blaen yn ystod pandemig COVID-19, ac mae'n atal buddsoddi mewn bysiau dim allyriadau.