Task: Question Generation
Input (English): Context : Pobol y Cwm (People of the Valley; Welsh pronunciation: (ˌpɔbɔl ə ˈkʊm)) is a Welsh-language television soap opera which has been produced by the BBC since October 1974. 
Subject : Pobol y Cwm 
Relation : original network
Output (English): Where network aired Pobol y Cwm?