Mae GYD wedi sefydlu yn y rhan helaethaf o Lundain Fwyaf ac mewn rhai siroedd cyfagos. Mae ymdrechion yn cael eu gwneud ledled y DU i leihau ei boblogaeth, ei ledaeniad a’i effaith ar yr amgylchedd.
OPM is established in most of Greater London and in some surrounding counties. Efforts are being made across the UK to minimise their population, spread and impact on the environment.