We need to change the way we travel in order to tackle that, and that means making more use of public transport, more walking and cycling, and fewer emissions from vehicles.
Er mwyn gwneud hyn, mae angen i ni leihau nifer y siwrneiau a gymerir gan geir preifat a chynyddu nifer y bobl sy'n cerdded, beicio a defnyddio trafnidiaeth gyhoeddus.