The central government has tweaked the windfall gains tax on fuel exports, raising the levy on petrol to Rs 2.5 per litre while cutting the diesel tax from Rs 16 to Rs 8.5 per litre. The windfall tax on aviation turbine fuel (ATF) remains unchanged. These adjustments, effective October 16, were announced by the Central Board of Indirect Taxes and Customs (CBIC) and apply for a fortnight. Duties on petrol and diesel meant for domestic consumption stay the same, so retail pump prices are unaffected.
The government has not published a product-wise explanation for this revision. The reporting only confirms the new rates and notes that they are revised every fortnight depending on average crude oil prices over the last 15 days. The likely driver is the movement in international product prices and refining margins since the previous review.
The diesel levy has been on a downward path, easing from Rs 25 in mid-September to Rs 20 on October 1, and now to Rs 8.5. This suggests average diesel prices or margins have softened over the review window. Petrol, by contrast, has seen its levy lifted from a low base of Rs 0.5 to Rs 2.5, indicating that petrol prices or margins have firmed relative to the previous period. ATF remains unchanged, implying little change in average jet fuel prices or margins. These moves are consistent with a levy that tracks each product's own price trajectory, though the government has not confirmed this.
The windfall gains tax is levied as a Special Additional Excise Duty (SAED) on exports. The CBIC reviews the rates every fortnight, adjusting them based on the average international prices of crude oil, petrol, diesel and ATF recorded since the previous review. When global prices of refined products rise, the levy may be increased; when they ease, the levy can be reduced. This approach allows the government to respond quickly to changes in international markets without locking the industry into a fixed rate for an extended period.
The latest revision comes against a backdrop of crude oil prices around $95 per barrel, according to LSEG shipping and oil price data cited by Reuters. The US-Iran war and the Russia-Ukraine war have boosted freight and insurance rates, contributing to elevated crude prices. The fortnightly reset means the levy captures part of the extra margin refiners earn when global prices spike, but with a lag because it is set on the average of the past 15 days.
The export levy is a per-litre deduction from the export margin. What the refiner keeps is the rise in global margins minus the export duty. The diesel cut of Rs 7.5 per litre is a meaningful relief for refiners with large diesel export volumes. For every 10 crore litres of diesel exported, the reduction translates into approximately Rs 75 crore less tax. The petrol increase of Rs 2 per litre is a modest drag, starting from a low base. Since diesel volumes are far larger, the net effect for most refiners is positive.
The impact is not spread evenly.
This significantly cushions the direct impact on Reliance. Other refiners, such as Mangalore Refinery and Petrochemicals (MRPL) and Chennai Petroleum, are more directly exposed because they pay the levy on their exports and lack a large marketing business to offset it.
This shows how large the levy has been. The latest diesel cut should improve the economics of overseas sales, depending on international product prices, crude procurement costs, freight rates and refining margins. Transcript
The differential tax treatment between petrol and diesel exports could influence refiners' product mix and export volume decisions, but the evidence is limited. Refinery yields are largely fixed by crude slate and configuration, so a Rs 2 petrol increase against a Rs 7.5 diesel cut is more likely to affect export timing and destination than the yield mix. This is an inference, as I found no company disclosure on it.
Indian Oil does not expect a major sustained exportable surplus of diesel or petrol, given domestic demand. It expects seasonal exports, mainly of naphtha and furnace oil. The levy's effect on public sector supply is therefore likely modest. Refinery output is at its limit—Indian Oil's refineries ran at 109.4% utilisation in Q1 FY27—so the levy mainly shifts allocation at the margin. Transcript +2
The government has not disclosed why the ATF levy was left unchanged. The ATF rate was Rs 10.5 from October 1, so it presumably stays at that level. An unchanged levy is consistent with average ATF prices or margins not moving enough to warrant a change. International jet fuel markets have been affected by refinery disruptions and supply chain issues, but the fortnightly average may not have shifted enough to trigger a revision.
The absence of changes in existing duty rates on petrol and diesel cleared for domestic consumption means the arbitrage incentive between domestic sales and exports shifts only through the export side. Public sector oil marketing companies (OMCs) sell mostly in the domestic market at administered prices. Refiners with large export exposure have the real choice, such as MRPL, Chennai Petroleum and Nayara Energy.
The Rs 10 per litre excise cut of March 27 was kept off retail prices. It was meant to cut OMC under-recoveries, not to lower pump prices. The total excise burden fell from about Rs 21.90 to Rs 11.90 per litre on petrol and from Rs 17.80 to Rs 7.80 per litre on diesel. Estimates of the annualised revenue loss run to Rs 1.55–1.70 lakh crore if the structure holds through FY27. Reversing it would raise the price or OMC losses, so a fixed domestic duty is the simpler anchor.
The domestic duty stabilises retail prices and OMC finances. The export levy is a flexible instrument that tracks average international prices and is reviewed every fortnight. It also takes some windfall from exporters when prices spike. The government has chosen to bear the fiscal cost of stable domestic prices while using the export levy to manage supply and capture extraordinary gains.
The fortnightly reset enables the central government to capture incremental revenue from refining sector windfalls during periods of high international crude prices. The first-fortnight SAED gain was estimated at about Rs 1,500 crore. The Rs 10 per litre domestic excise cut cost about Rs 7,000 crore for the same 15 days. On those figures, the export levy offsets only a fraction of the duty forgone.
The CBIC faces a trade-off between maximising fiscal revenue through windfall taxes and maintaining the competitiveness of Indian refined product exports in global markets. The levy was imposed to discourage exports and keep diesel and ATF available at home. Raising the rate cuts exports, so maximising revenue and keeping exports competitive pull against each other. The government has put domestic availability first.
Rates follow prices. The levy is cut as product prices ease, which preserves export economics. Cutting it improves the economics of overseas sales. Analysts note the levy takes only the part of the margin above normal. If export margins rise by more than the levy, refiners still earn above normal. The differential tax adjustment—increase on petrol, decrease on diesel—reflects the government's assessment of relative export profitability and market conditions for each fuel type, though it has not published that assessment.
The fortnightly review mechanism means future rates will continue to depend on developments in international crude oil and refined-product prices. If global oil prices remain elevated because of supply disruptions or geopolitical tensions, the government could continue to calibrate the levies to balance domestic availability, refinery economics and fiscal considerations. Conversely, a sustained decline in international crude and product prices could reduce the rationale for maintaining high export duties.
For refiners, the immediate impact of the October 16 revision is a lower tax burden on diesel exports and a slightly higher burden on petrol exports. The reduction also demonstrates the government's continued reliance on a flexible, market-linked approach to petroleum export taxation as global energy markets navigate geopolitical uncertainty and changing supply conditions. The honest way to follow this is to watch three things together: crude oil prices, the fortnightly duty notification, and the refining-margin commentary companies give in their quarterly results.
