§ Mr. Harold Walker
asked the Secretary of State for the Environment when he expects to be able to raise into a cleaner category the classification of the River Don in South Yorkshire.
§ Mr. Eldon Griffiths
I refer the hon. Member to Volume 2 of the Report of the River Pollution Survey 1970. Chapter 7 includes forecasts of upgradings provided by river authorities and also points to the many factors which can affect forecasts of this nature.