गण्डक नहर प्रणाली का गठन कब किया गया ? - When was the Gandak Canal System formed? - Gandak Nahar Pranali Ka Gathan Kab Kiya Gaya ? UP GK in hindi, मिट्टी कृषि एवं पशुपालन 1974 question answers in hindi pdf 1975 questions in hindi, Know About 1972 UP GK online test UP GK notes in hindi quiz book 1976