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The effects of various oxygen partial pressures (PO2) during melt processing on the superconducting properties of fabricated NdBa2Cu3Oy(Nd123) superconductors have been systematically investigated. Unlike in air or O2, samples melt-processed in reduced oxygen atmospheres exhibited unprecedentedly high Tc's of 95-96 K with a sharp superconducting transition. Especially, for a sample melt-processed in 0.1% O2in Ar, the magnetization hysteresis (M-H ) loop was kept open up to 7 T at 77 K and for the field parallel to the c-axis of the sample (H//c), implying that very effective flux pinning can be achieved in high magnetic fields.