Cyfyngwch eich canlyniadau yn ôl:
- Pob un
- Environmental protection -- Wales, 5 canlyniadau
- Pollution -- Wales, 3 canlyniadau
- Waste disposal in the ground -- Great Britain, 1 canlyniadau
- Environment, 1 canlyniadau
- Birds -- Wales -- Dyfi, River, Estuary, 1 canlyniadau
- Copper mines and mining -- Wales -- Parys Mountain, 1 canlyniadau
- Natural areas -- Wales -- Merionethshire., 1 canlyniadau
- Pollution, 1 canlyniadau
- Power resources -- Wales, 1 canlyniadau