1. The build-up, litre by litre · PPAC, as on 01.10.2025

Source: PPAC Ready Reckoner, FY2025-26 H1 edition, Tables 8.2–8.5 and 8.16A (price build-up of Petrol/Diesel at Delhi, PDS Kerosene at Mumbai; customs & excise duty schedule), as on 01.10.2025.

Petrol and diesel sit entirely outside GST — Table 8.16A of the Ready Reckoner lists them (with crude oil and ATF) under "products on which GST is not levied." Instead they carry a four-part central excise stack, each component a flat ₹/litre regardless of the crude price: Basic Excise Duty, Special Additional Excise Duty, the Road & Infrastructure Cess, and the Agriculture Infrastructure & Development Cess. Petrol's stack (₹21.90/l: 1.40+13.00+5.00+2.50) is heavier than diesel's (₹17.80/l: 1.80+10.00+2.00+4.00) — a deliberate policy tilt against private motoring versus freight and agriculture. Because none of these four components move with crude, they are the lever government has historically pulled to cushion pump prices when crude spikes, and the reason the "full pass-through" scenarios below likely overstate how much of a crude rally would actually reach the pump.

2. Where crude stood on 5 August 2026 · Rigzone + OilPriceAPI, cross-checked against PPAC's own weighting

5 August 2026 snapshot, kept for the method trail:

Rigzone's public quote widget put Brent at $78.85/bbl and WTI at $75.02/bbl on 5 August 2026. OilPriceAPI's feed for that day agreed closely — $78.87 and $74.84 — and additionally carried Dubai ($78.04) and Oman ($78.26) benchmarks, the two sour-crude grades PPAC uses to build the Indian basket. Applying PPAC's own published weighting formula (78.71% average of Oman/Dubai, 21.29% Brent Dated) to that day's quotes gives an implied Indian basket of $78.30/bbl — up 12.0% on the $69.89/bbl PPAC actually published as the Jul–Sep 2025 quarterly average (Table 8.1).

Data-quality note: OilPriceAPI's market-overview endpoint returned two conflicting fields for the same benchmark in the same response — "Brent Crude Oil" at $78.87 (matching Rigzone and the dedicated price endpoint) alongside a separate "BRENT_SPOT_USD" field at $91.82, and an equivalent split for WTI ($74.84 vs "WTI_SPOT_USD" $84.25). This piece uses the $78.87/$74.84 figures, corroborated by two independent sources; the higher pair looks like a stale or differently-scoped cache and is flagged here rather than silently reconciled.

PPAC's own monthly Indian-basket series (Table 8.1) runs only to September 2025 in this Ready Reckoner edition, so the "5 Aug 2026" figure above is not a PPAC-published number — it is PPAC's published formula applied to that day's OilPriceAPI inputs, an ≈11-month gap from the last officially published monthly print.

3. Crude scenarios, held-duty basis · Delhi RSP under five crude levels

Method: dealer price = crude-equivalent (Indian basket $/bbl × ₹88.32/$ ÷ 158.987 litres/bbl) + a fixed refining-and-marketing wedge (₹14.24/l petrol, ₹15.18/l diesel, backed out of the PPAC Jul–Sep 2025 baseline). Excise duty, dealer commission and the effective VAT rate are held at their 01.10.2025 PPAC levels — i.e. no policy offset. Past-year Brent high/low ($117.38 / $59.59, OilPriceAPI 365-day history as of 5 August 2026) converted to an Indian-basket analogue by scaling proportionally to 5 August 2026's Brent-to-basket ratio, since a historical Oman/Dubai series was not available to apply PPAC's exact formula at those dates. The 25 Sep 2026 row uses the same formula and the same held FX rate (₹88.32/$) applied to $101.07/bbl, PPAC's own Indian Basket figure for that date as reported by Business Standard and Yahoo Finance — not an OilPriceAPI/Rigzone pull like the other rows, since this piece's research environment could not reach either live-quote provider or ppac.gov.in directly at the time of this update; a real 25 September rupee rate would also differ from the held ₹88.32/$, which this row does not model, consistent with every other row in this table.

The scenario range makes the excise lever visible: a 97% swing in crude (past-year low to high) would, on a naive full pass-through, move Delhi petrol by ≈43% (₹87.65 to ₹125.71) — a smaller swing than crude's own, because the flat-rate excise and commission layers don't move at all, and only the dealer-price and VAT layers scale. In practice the swing at the pump has historically been smaller still, because government has repeatedly cut excise duty when crude spiked (and raised it when crude fell) specifically to smooth this pass-through — a policy choice this build-up deliberately does not model, so as to isolate what the tax structure alone would do.

4. All 35 state capitals · filter by state and crude scenario

State VAT is applied on top of the same national dealer price, excise and commission, so the state-to-state spread is almost entirely a tax-policy spread, not a supply-cost spread. PPAC publishes actual pump prices per state capital (Table 8.14) but not the state-by-state VAT build-up math, so the "effective incidence" column below is backed out of the published RSP — it captures state VAT plus any local freight differential baked into that city's dealer price, not the bare statutory VAT rate alone.

Source: PPAC Ready Reckoner Table 8.14, "Retail Selling Price of petroleum products at State capitals/UTs as on 01.10.2025," sourced by PPAC from IOCL.

5. Enter a crude price, pick a blend · E0 to E35, all 36 states and UTs

Petrol at the pump also runs through an ethanol blend before it reaches the tank. Ethanol is excise-exempt, so the more of the litre it makes up, the less central excise the government collects on that litre — and, as the map below shows, that foregone excise outweighs ethanol's own cost premium over crude-linked petrol, so a cost-reflective blended price actually falls slightly as the blend rises. This map reuses the India state boundaries from this site's grain-cultivation/FCI-storage map, re-priced state by state.

Capacity is not the constraint. India's installed ethanol distillery capacity is roughly 2,000 crore litres for ESY2025-26 (CareEdge estimate), against 904.8 crore litres actually drawn by PSU OMCs in ESY2024-25 (PPAC Table 6.10) — about 1,095 crore litres of spare, already-built capacity sitting unused. Because ethanol's cost is fixed annually by government notification rather than tracking crude, a higher blend share structurally dampens how much a crude spike passes through to the pump: modelling the FY2021-22–FY2025-26 crude range ($69.89–$93.15/bbl) through the build-up above, petrol's cost-reflective price would have swung ₹15.43/litre at E0 versus ₹12.34/litre at E20 — about 20% less volatile. That spare capacity means blending can be pushed harder during a crude shock without waiting on new plants; the real limit is feedstock supply (46.4% of ethanol now comes from maize, per Table 6.10A) competing with food-security demand for the same grain, not distillery capacity itself.

Model: excise duty (₹21.90/l petrol) applies only to the non-ethanol share of the blend; ethanol costed at ₹71.16/l, OMCs' ESY2025-26 weighted-average delivered procurement cost (ex-mill average ₹66.61/l plus GST and transport, per government disclosures reported early August 2026). State VAT/GST uses each state's effective incidence from Section 4. Diesel is not ethanol-blended in India at scale, so it does not change with the blend selector. In practice, pump prices today do not vary by blend grade — OMCs sell E10/E20/E0 at the same notified price and absorb the difference internally; this is the cost-reflective price implied by the tax structure, not a price you will see posted differently at two pumps.

6. Checked against the OMCs' own websites · coverage, not live cross-validation

IOCL, BPCL and HPCL were checked directly (5 August 2026) to see whether any publishes a live, scrapable multi-city price table that could validate the figures above against today's actual pump price. None does:

• IOCL (iocl.com/petrol-diesel-price, page last updated 03/08/2026) carries no live price table. It routes the public to an SMS lookup ("RSP <dealer code>" to 92249 92249) against a published list of 42 dealer codes, or the IndianOil ONE app. The city list overlaps closely with PPAC's 35 state capitals, with minor naming differences (e.g. Jammu listed separately from Srinagar; Vijayawada/Visakhapatnam rather than Amaravati for Andhra Pradesh).
• BPCL (bharatpetroleum.in, petro-prices page, site last updated 04/08/2026) likewise has no live table — only a station locator and downloadable PDFs titled "Price Build-up of Petrol/Diesel at Delhi at BPCL Retail Pump Outlets," Delhi-only, structurally identical to PPAC's own Table 8.4/8.5.
• HPCL's direct price-page URL redirected to its generic homepage; no live table was reachable there either.

So PPAC's Table 8.14 — a snapshot dated 01.10.2025, not a live feed — remains the most complete multi-location source actually available in machine-readable form. The scenario figures in this piece should be read as "PPAC's last-published baseline, re-priced under a crude assumption," not as today's actual pump price at any of these 35 cities.

7. The link to petrochemicals · same crude, different tax regime

Naphtha and other petrochemical feedstocks come off the same crude barrel and the same refinery gate as petrol and diesel, but Table 8.16 draws a hard administrative line: petrol, diesel, ATF and crude oil sit outside GST under the flat-rate excise regime detailed above; virtually everything else — including the organic-chemical and polymer imports covered in this site's textile import-export strategy piece — is priced and taxed under GST (IGST plus, on imports, the BCD/AIDC/SWS stack detailed in the HSN Ch.27 dashboard). That is the structural reason India's petrochemical import bill is far more exposed to a crude/rupee swing than the pump price is: fuel pricing has a flat-rate excise shock absorber built in; ad-valorem GST-rated chemical imports do not.

Method. Crude-to-litre conversion uses 158.987 litres/barrel and a held exchange rate of ₹88.32/$ (PPAC's own September 2025 average, Table 8.13B note) across all scenarios — a real crude move would also move the rupee, which this piece does not model. Refining-and-marketing wedge and state effective-incidence figures are both backed out of PPAC's own published prices, not independently sourced cost data; PPAC does not publish a crude-vs-margin split. Crude prices, original 5 August 2026 build: Rigzone (rigzone.com/news/oil_gas_price) and OilPriceAPI (oilpriceapi.com), both queried 5 August 2026, 02:00 UTC. Crude price for the 25 September 2026 row added in this update: PPAC's own Indian Basket figure ($101.07/bbl), attributed via Business Standard and Yahoo Finance's contemporaneous coverage of PPAC's published series rather than a direct fetch of ppac.gov.in, Rigzone or OilPriceAPI, all of which returned blocked-egress errors in this piece's research environment at the time of this update; Brent ($104–105/bbl) and WTI (~$93/bbl) for the same date via Tradingeconomics, ConvexTrade and OneValor. State price baseline and duty schedule: PPAC Ready Reckoner FY2025-26 H1 edition, Tables 8.1–8.17.