India’s decision to halt Russian oil purchases as part of a wider trade deal with the U.S. announced last week would mark the most dramatic rupture in Moscow–New Delhi energy ties in half a century if the commitment holds. And it comes at the precise moment Washington has been trying to force this break since the first weeks of the Ukraine war. For years, India has been one of the single biggest financial pressure?valves keeping Russia’s wartime economy alive — buying millions of barrels a day at steep discounts, refining…