India now gets about 12-18% of its oil from Russia (depends on how you count "indirect" purchases). The problem with embargoing Russian oil is that they are the no. 2 exporter (about 11% of Global exports). Basically Russia produces about 10-11 million barrels per day (mbd) but only uses about 3 mbd domestically, allowing them to export the remaining 7-8 million. The US produces more, but it consumes most of what it produces, leaving it as the No. 3 exporter, and that number is falling as we pull back on oil exploration and investment, making Russia and Saudi Arabia more important each year to the global oil market.
Demand for oil is relatively inelastic -- e.g. estimates are something like -.05 in the short term and -.03 in the long term. So just disappearing Russian oil from the market would result in a ~220% increase in oil prices (a very rough estimate, but a ballpark) -- oil would cost roughly $200. That would destroy the world economy and cause mass starvation as well.
So what happens is that an embargo is created and the supply drops, and prices go up, by, say, $20, and then Russia comes along and says "We'll give you a $15 discount if you buy our oil". Then there are lots of buyers, of which India is only one, that agree to this. The end result is that Russia makes $5 more per barrel than before the embargo, but they sell a bit less oil. Everyone else pays a bit more. As this happens, word gets out that Russia is selling oil for $15 below market and the world price falls. As the price falls, the discount narrows. Presently, the discount is $5 (and it's still falling).
In the same way, the US and Europe continue to buy Russian oil, often laundered through third parties. But they all pretend that they have moved off of Russian oil, even though everyone knows it's just gone through some shell companies.
There are now attempts to set a price cap on Russian oil by the G7 nations -- Russia sells about 3 mbd to G7 nations now. But again, this same process will happen. Russia will say "no, I won't sell to you at this low price", at which point the G7 nations have to get their oil from somewhere else, and they outbid existing buyers so the price goes up, then Russia offers a discount that's a little bit lower than the price increase, and prices fall down a bit, but not all the way to what they were before. Russia makes more money per barrel, but sells a bit less. Everyone else pays more per barrel.
Many don't remember the Arab oil embargo of the 1970s, but basically OPEC announced it was refusing to sell oil to Western powers in order to punish them for supporting Israel in the 1973 war. At that time, people understood that not being able to buy OPEC oil would cause them to suffer, but that knowledge appears to have been lost, and now we are imposing self-embargoes of oil against the No 2 supplier. But the world is a lot bigger now, with most of Russia's oil being sold to Asia, and Asia still understands the basic supply-demand relationships that the West appears to have forgotten. You can't expect the world to voluntarily agree to $200 oil. They will continue to buy from the lowest bidder, even if the G7 nations self-impose a higher price for their own purchases.
All these attempts to prevent two nations from trading in commodities -- e.g. banning the insurance of Russian oil in London -- don't actually work, as both China and Russia now offer insurance on Russian oil and also maintain their own fleet of tankers and there is a vast network of pipelines running across central asia. The result will again be that the market share of London insurers will fall as ships are insured elsewhere. The economic share of shipping in Europe will fall as other nations' fleets are used, etc. Oil is just too important to the functioning of the global economy for nations to agree to a doubling of its price.