The shift to the new marine norms has started to impact a few oil cracks. The gross refining margins (GRMs) all across have started to improve. Probal Sen, Senior VP at Centrum Broking, said GRMs are improving due to the shutdown of plants, maintenance issues in Asian plants. He said most estimates are lowering demand forecast for crude, and expects the margin to be high in Q2 and Q3 due to low output. He does not expect any inventory gain for oil marketing companies (OMCs) In Q1.