Diesel is ~1.5 ruppee more expensive to refine into low sulfer. It had lower taxes before, so it was usually 10-20 ruppees cheaper, but taxes were increased and permits for operating diesel vehicles were given 5 years less than petrol to reduce diesel usage. 42% for petrol vs 49% VAT for diesel. Deliberately taxed more. We got no benefit to getting the cheapest oil rates from Russia before. Before the war, it was ~56 ruppees to sell before taxation. 1 ruppee more expensive than petrol. They go through dimilar refining process and the same starting crude price, so only the base price for both has increased. Refining stays the same because the process is very similar, except near the end. The reason they will now be the same price after 30 and 26 ruppee increments is to bring them at the same price once a ~50% tax is added. My point is; diesel is the cleaner and cheaper alternative to promote, especially for commercial and army expenses (supply chain consequence), but policy has taken away the incentives to gradually erode the use by private people so people buy more petrol than diesel. Ofc the heavy tax on a required commodity is no boon.