Sanctions will always drive up inflation. The entire point is that you're willing to suffer some pain in the hopes of putting even more pressure on your target.
If the US wanted to lower oil prices, they'd drop sanctions. But even more than they want cheap oil, they want Russia to leave Ukraine.
India gets stuck in the middle. They can't as easily absorb an increase in oil prices. So the US has to decide how much pressure to put on India to participate in sanctions, knowing what damage it will do to Indian allies, whom they need for other things.
If the US wanted to lower oil prices, they'd drop sanctions. But even more than they want cheap oil, they want Russia to leave Ukraine.
India gets stuck in the middle. They can't as easily absorb an increase in oil prices. So the US has to decide how much pressure to put on India to participate in sanctions, knowing what damage it will do to Indian allies, whom they need for other things.