IIP base year shifts to 2022-23

MoSPI's expert committee report clears a rebuilt Index of Industrial Production series, with the official switch from 1 June 2026.

What happened

• The Ministry of Statistics and Programme Implementation (MoSPI) released the report of the Technical Advisory Committee on Base Year Revision of the All-India Index of Industrial Production (TAC-IIP), accepting a shift of the index's base year from 2011-12 to 2022-23.
• The committee was constituted in September 2024 under Dr. Mridul K. Saggar, Professor at IIM Kozhikode, and drew in academics, chief economists, senior government officials and State Directorates of Economics and Statistics (DESs).
• It held eleven meetings, issued three discussion papers for public consultation (substitution of factories, a chain-based IIP, and seasonal adjustment), and convened three consultative workshops before finalising the design.
• The revised basket carries 1,042 products mapped to 463 item groups, aligned to the National Industrial Classification (NIC-2025).
• The new 2022-23 series launches officially on 1 June 2026, presenting index values from April 2023 onward, including Quick Estimates for April 2026, with sectoral and use-based breakdowns.

Background & context

The Index of Industrial Production (IIP) is a short-term composite indicator that measures the volume of production of the industrial sector relative to a chosen base period, fixed at a value of 100. It is compiled and released monthly by the National Statistical Office (NSO) under MoSPI, with a lag of roughly six weeks; the first release for a month is a Quick Estimate that is later revised. Because it is a volume index rather than a value index, the IIP strips out price effects and tracks real industrial momentum, which is why it feeds directly into GDP back-series estimation, the Index of Eight Core Industries cross-checks, and the Reserve Bank of India's reading of the industrial cycle.

A base year is the benchmark period whose production pattern and item weights anchor the whole index. Over time the industrial structure drifts — new products appear, old ones fade, and consumption baskets change — so an ageing base steadily misrepresents reality. International statistical practice, reflected in the United Nations guidance on index numbers, recommends revising the base roughly every five years. The IIP series running until this revision was anchored to 2011-12, making it well over a decade old and increasingly unable to capture sunrise sectors. The earlier base-year milestones in the IIP lineage include 1937, 1946, 1951, 1956, 1960, 1970, 1980-81, 1993-94, 2004-05 and 2011-12, so the move to 2022-23 is the latest step in a long re-basing tradition rather than a one-off event.

The legal and institutional spine matters for the exam. The IIP is compiled under the Collection of Statistics Act, 2008 framework that empowers MoSPI's data gathering, and the source data flow in from administrative ministries and agencies — the Department for Promotion of Industry and Internal Trade (DPIIT) for the bulk of manufacturing items, the Ministry of Mines and others for mining, and the Central Electricity Authority for electricity. The revision was steered by the TAC, an expert advisory body, while the final series and its weights are owned and published by the NSO. This division — an independent technical committee recommending, the statistical office adopting and releasing — is the standard governance pattern for India's official statistics and parallels how the Consumer Price Index and Wholesale Price Index baskets are periodically reviewed.

It is worth placing the TAC-IIP's methodology choices in context. The committee circulated discussion papers on three live questions in industrial-index design. The first, substitution of factories, deals with how to replace units in the producing sample that shut down or stop reporting, so that the index does not silently drift as its panel of factories ages. The second, a chain-based IIP, refers to a method in which weights are updated more frequently — effectively re-linking the index period to period rather than holding a single fixed base for a decade — which keeps the basket continuously representative but is harder to compile; flagging it signals the direction the series may eventually take. The third, seasonal adjustment, addresses the predictable calendar swings (festival months, harvest cycles, the year-end push) that distort raw month-on-month readings, so that the underlying trend is visible. Putting these three on public consultation before re-basing reflects the consultative, internationally-benchmarked approach MoSPI now follows.

For Prelims

• What it is: Index of Industrial Production (IIP) — a monthly volume index of industrial output, base value 100, compiled by the National Statistical Office under MoSPI.
• Base year revised: from 2011-12 to 2022-23, on the recommendation of the TAC-IIP report; official launch 1 June 2026.
• The committee: TAC-IIP constituted September 2024, chaired by Dr. Mridul K. Saggar (IIM Kozhikode); held 11 meetings; released three discussion papers for public consultation.
• New basket: 1,042 products → 463 item groups, aligned to NIC-2025 (up from the 2011-12 basket built on the older classification).
• Widened scope — newly added activities: Minor Minerals · Rare Earth Minerals · Gas Supply · Water Supply · Sewerage & Waste Management.
• New sub-indices: separate indices for renewable vs non-renewable electricity; Mining & Quarrying split into three — Fuel Minerals, Metallic Minerals (including Rare Earth Minerals), and Non-Metallic Minerals (including Minor Minerals).
• Linking method: the new series uses the Geometric Mean to link the 2011-12 and 2022-23 series; linking factors are computed for the General Index and the Sectoral Indices, so historical comparisons stay possible.
• The three sectors (sectoral classification): the IIP is split into Mining, Manufacturing and Electricity, with Manufacturing carrying by far the largest weight.
• The six use-based categories: Primary Goods · Capital Goods · Intermediate Goods · Infrastructure/Construction Goods · Consumer Durables · Consumer Non-Durables. This is the lens most quoted in monthly commentary.

What it is NOT: the IIP is not a price index — it measures physical volume of output, so it is distinct from the CPI and WPI (which track prices) compiled by MoSPI and the Office of the Economic Adviser (DPIIT) respectively. It is not the Index of Eight Core Industries (released by the Office of the Economic Adviser, covering coal, crude oil, natural gas, refinery products, fertilisers, steel, cement and electricity, with about a 40% weight in the IIP) — the Core Index is an input to the IIP, not the IIP itself. It does not measure GDP, GVA or capacity utilisation, and it does not currently cover the unorganised/informal manufacturing sector, which is one of its standing limitations. Finally, the IIP is not released by the RBI or NITI Aayog; MoSPI's NSO owns it.

Why it matters

An index is only as honest as its weights. With a base frozen at 2011-12, the IIP increasingly under-weighted the parts of industry that have grown — renewables, electronics, modern services-linked manufacturing — and over-weighted slowing lines, so month-to-month readings risked telling a stale story about where the economy actually moves. Re-basing to 2022-23 resets those weights to a recent, representative production structure and pulls in activities the old series ignored. The explicit addition of Rare Earth Minerals and a dedicated split of Mining into fuel, metallic and non-metallic streams is significant given the strategic-minerals debate and India's critical-minerals push; the new renewable vs non-renewable electricity sub-indices let analysts read the energy transition directly off the industrial data for the first time.

Adding Water Supply, Gas Supply, and Sewerage & Waste Management widens the index from a narrow factory-and-mine measure toward the broader industrial-and-utilities economy, improving its alignment with the System of National Accounts. Because the series links back to 2011-12 via geometric-mean linking factors, policymakers, the RBI and markets keep a continuous time series rather than a break — which protects the IIP's role in nowcasting growth and timing monetary decisions. The problem the revision addresses is therefore measurement drift: an old base quietly biases the published growth rate, and a biased high-frequency indicator can mislead both policy and investment.

For Mains