Refining margins for India’s biggest state-owned refiners have dropped in recent months amid more difficult access to Russian crude and soaring freight rates due to the Red Sea disruption to crude shipments, analysts and traders tell Bloomberg. For most of 2023, Indian refiners enjoyed high refining margins and profits as they imported cheap Russian crude at $20 a barrel and more below international benchmarks. Margins started eroding last quarter, although they are still higher than before the Russian invasion of…