The Centre has decided to refer back the matter regarding cess on water used by hydro-electric power generating units under the water (Prevention & Control of Pollution) Cess Act, 1997, to the Standing Committee of Parliament.A decision to this effect was conveyed to the Himachal Pradesh Chief Minister, Mr. P.K. Dhumal, when he called on the Union Minister for Forests and Environment, Mr Suresh Prabhu, last evening.