Blitz Bureau
NEW DELHI: For a generation of readers, “the eight core industries” has been a fixed phrase in Indian economic writing — the monthly reading that tells you how coal, oil, gas, refineries, fertiliser, steel, cement and electricity are doing, and therefore how the productive spine of the country is doing. That phrase is now out of date. The Office of the Economic Adviser in the Department for Promotion of Industry and Internal Trade has rebased the Index of Core Industries to 2022-23, and in doing so has added a ninth: iron ore.
The change is quiet, technical and consequential. It alters what the index measures, how it is computed, and — for anyone comparing this year’s number with an older one — whether the comparison means anything at all.
Index of Core Industries · new series, base 2022-23 : The nine industries and what each is worth in the index
| Sector / Industry | Weight (%) |
|---|---|
| Electricity | 30.932 |
| Refinery products | 22.572 |
| Steel | 17.584 |
| Crude oil | 7.430 |
| Coal (raw coal only) | 5.596 |
| Iron ore — new in this series | 4.905 |
| Cement | 4.410 |
| Natural gas | 3.841 |
| Fertilizers | 2.731 |
Source: Press release on the new series of the Index of Core Industries with base year 2022-23, Office of the Economic Adviser, DPIIT, Ministry of Commerce and Industry, issued 20 July 2026 (PIB release 2286615). Weights sum to 100. Blitz has verified the sum and every derivation below from the annexures published with that release.
Three changes, and why each was made
The first is the new entrant. Iron ore has been brought in, in the Department’s own words, “owing to intensive use of Iron ore in the production process, and its contribution to industrial development”. It is the raw material at the head of the steel chain, and a country building at India’s present rate has a direct interest in knowing what is coming out of its mines before it knows what is coming out of its furnaces.
The second change concerns steel, and it is subtler. The old series used net production data. The new one uses gross production, so that the core index lines up with the Index of Industrial Production, which already worked on gross. Two indices that purport to measure the same industry ought not to measure it differently; that gap has now closed.
The third change removes a distortion that had been quietly inflating the index. In the old series, coal appeared three times over — raw coal, coal middling and washed coal. But middling and washed coal are made from raw coal. Counting all three counted the same tonne more than once. The new series retains raw coal alone. This is the sort of correction that never makes a headline and improves every number that follows it.
Middling and washed coal are made from raw coal. Counting all three counted the same tonne twice. The new series counts it once.
What changed on 20 July 2026
• Base year moves from 2011-12 to 2022-23.
• Iron ore added; eight core industries become nine.
• Steel computed on gross, not net, production.
• Coal middling and washed coal dropped; raw coal retained.
• Weights derived from the IIP 2022-23 weights, pro-rated to 100.
• Linking factor between the series: 1.47.
• Old 2011-12 series discontinued.
• Release day: the 20th of the following month.
The number that bridges the break
Whenever a statistical series is rebased, the old numbers and the new ones stop being directly comparable, and the honest way to handle that is to publish a bridge. The Department has done so. The linking factor between the 2011-12 and 2022-23 series of the core index is 1.47, computed as the geometric mean of the monthly old-series index for 2022-23 divided by the geometric mean of the monthly new-series index for the same year. The formula is published, so a user can derive the factor for any individual sector rather than taking the aggregate on trust.
This matters more than it sounds. A reader who sets a growth rate quoted on the old series beside one quoted on the new is comparing two different instruments, and the difference between them is not error but arithmetic. The back series of the new index from April 2023 has been placed on the Office of the Economic Adviser’s portal precisely so that the comparison can be made properly.
What the new instrument is showing
On the new series, the Index of Core Industries grew 5.0 per cent in June 2026 over June 2025, up from 3.2 per cent in May. Cumulative growth for April to June 2026 was 3.6 per cent, against 1.0 per cent in the same quarter of the previous year — the sharpest part of the picture, and the part that carries into the year rather than describing a month.
Underneath, the pattern is one of two economies moving in opposite directions. Iron ore rose 43.9 per cent, electricity 9.8 per cent, cement 9.8 per cent, steel 4.6 per cent and coal 1.4 per cent. Natural gas, crude oil, refinery products and fertilizers all fell. Blitz has computed what each of those movements contributed to the headline: electricity alone accounts for about 3.0 percentage points of the 5.0, and iron ore for about 2.2, while the four falling sectors together subtract about 1.7 points. Put plainly, June’s growth was made in power stations and mines, against a drag from the hydrocarbon block.
Computed by Blitz from the published weights and growth rates . Who moved the index in June 2026, in percentage points
| Sector / Industry | Growth Rate (%) |
|---|---|
| Electricity | +3.03 |
| Iron ore | +2.15 |
| Steel | +0.81 |
| Cement | +0.43 |
| Coal | +0.08 |
| Refinery products | −1.06 |
| Crude oil | −0.31 |
| Natural gas | −0.28 |
| Fertilizers | −0.09 |
Weight multiplied by year-on-year growth, divided by 100. Computed by this desk from Annexure I and Annexure II of the DPIIT release; the contributions sum to about 4.8 points against a published headline of 5.0, the small residue being the difference between a weighted-sum approximation and the index arithmetic itself. This table is a derivation, not a figure quoted from the release.
The concentration nobody mentions
One fact falls out of the weights and is worth setting down. Electricity, refinery products and steel together carry 71.088 of the index’s hundred points. Nearly three-quarters of what the country calls its core industrial reading is those three. The four sectors that fell in June — natural gas, crude oil, refinery products and fertilizers — carry 36.574 between them, better than a third of the index.
That is not a criticism of the index; a weighted index is meant to weight. But it does mean that a reader who takes the core index as a broad reading of Indian industry is taking a reading in which the power sector alone speaks for almost a third of the answer.
Why a rebasing is a sign of health
A statistical series that is never rebased is a series drifting away from the economy it claims to describe. Weights fixed in 2011-12 describe the industrial structure of 2011-12; used in 2026 they describe a country that no longer exists. Rebasing to 2022-23, aligning the steel definition with the IIP, removing the coal double count and publishing both the linking factor and the back series is, taken together, a piece of ordinary institutional maintenance done properly. It is also what makes the Viksit Bharat arithmetic checkable rather than merely asserted: a target is only as good as the instrument that will measure whether it was met.
Offered only as corrective advice, to help the work move faster: the release publishes the linking factor for the overall index and leaves users to compute it sector by sector from the formula. Publishing the nine sectoral linking factors alongside the aggregate would cost the Department a single table and would save every analyst, State government and journalist in the country from doing the same arithmetic nine times, occasionally differently. And where a government broadcaster or a ministry page still carries a growth rate on the discontinued 2011-12 series, a one-line note stating the series would prevent exactly the confusion this desk encountered while reporting this story.
