A sharp decline in oil prices unleashed demand for Indian government bonds on Monday, pushing the 10-year note to its best day since early April, as investors rushed to lock in higher yields ahead of the key US midterm elections.Brent crude futures fell nearly 5% to $108 per barrel in Asian trade, retreating from a six-month peak hit last week as Iranian negotiators left talks with Qatari mediators to end the war with the United States, and a draft proposal was being circulated with a follow-up meeting possible.For India, the world's third-largest oil importer and consumer, cheaper crude eases inflation and fiscal pressures, while tempering expectations of aggressive monetary policy tightening.The benchmark 6.94% 2036 bond yield fell nearly 10 basis points to 7.3154%, its steepest one-day decline since early April.