Index of Eight Core Industries: notes for bank exams

At a glance

The Index of Core Industries (ICI), still widely called the Index of Eight Core Industries, measures monthly output of the basic industries that feed the rest of the economy, such as electricity, steel and refinery products. It is an early indicator of industrial activity, released about a week before the IIP for the same month. Since July 2026 it uses base year 2022-23 and covers nine industries, after iron ore was added.

Key facts

Compiled by: Office of the Economic Adviser (OEA), DPIIT, Ministry of Commerce and Industry
Base year: 2022-23 (new series released 20 July 2026, effective from April 2023); earlier base 2011-12
Number of industries: nine (iron ore added in 2026); eight in the 2011-12 series
Largest weight (new series): electricity, 30.93%
Smallest weight (new series): fertilisers, 2.73%
Share in IIP: about 32.88% under the new base (40.27% under the 2011-12 series)
Release: provisional data around the 20th of the following month
Weights: derived from the IIP (base 2022-23) and rescaled to total 100

How it works

Weights in the old and new series.

Industry	Weight, base 2022-23 (%)	Weight, base 2011-12 (%)
Electricity	30.93	19.85
Refinery products	22.57	28.04
Steel	17.58	17.92
Crude oil	7.43	8.98
Coal	5.59	10.33
Iron ore	4.90	not included
Cement	4.41	5.37
Natural gas	3.84	6.88
Fertilisers	2.73	2.63

Method changes in 2026. Iron ore was added; steel now uses gross rather than net production (matching the revised IIP); only raw coal is counted in coal, to avoid double counting; and a linking factor of 1.47 connects the new series to the old one.

Why it matters. Because core industries make up about a third of the IIP and supply inputs to manufacturing and construction, a strong core sector reading usually signals a strong IIP print later in the month.

Recent developments

21 Oct 2026: Core sector output grew 7.9% in September 2026 (3.1% a year earlier); iron ore (18.4%), electricity (11.4%), coal (10.7%) and refinery products (10.3%) led, while fertilisers fell 11.7%. April–September growth was 5.1%.
20 Jul 2026: OEA released the revised ICI with base year 2022-23, adding iron ore as the ninth core industry and making electricity the heaviest component.

Exam traps

In the new series electricity, not refinery products, has the largest weight; refinery products led only in the 2011-12 series.
The index now has nine industries even though the name "eight core industries" is still used in news.
ICI is compiled by the OEA in DPIIT; the IIP is compiled by MoSPI (NSO).
Steel is in the index but iron ore was added only in 2026; cement is in, but cars, textiles and mining as a whole are not.

Quick check

Q: Which office compiles the Index of Core Industries? A: Office of the Economic Adviser, DPIIT.
Q: What is the base year of the current ICI series? A: 2022-23.
Q: Which industry was added in 2026? A: Iron ore.

Index of Eight Core Industries