Indian government bonds tumbled on Wednesday, reversing most of the previous session's sharp rally, as a fresh jump in oil prices and US Treasury yields rattled investors ahead of the Federal Reserve's policy decision. The benchmark 6.94% 2036 bond yielded 7.4772% at 10:50 a.m. IST, up 4 basis points from its previous close. The 10-year yield had dropped by nearly five basis points on Tuesday, its steepest single-day decline in three months, after failing to breach 7.50%.