CPI for Industrial Workers

Also called: CPI-IW · Topic: Inflation and Index Numbers: CPI, WPI, IIP and the Deflator · NCERT: Class 11, Ch 7 "Index Numbers"

Meaning

The Consumer Price Index for Industrial Workers (CPI-IW) is a monthly index of the retail prices of a fixed basket of goods and services that industrial workers' families usually buy. The Labour Bureau (Ministry of Labour and Employment) compiles it. Its current base is 2016=100, which replaced the 2001=100 series in 2020 [4].

It matters because the government uses it to revise the Dearness Allowance (DA) of its employees and to revise industrial wages [5]. So when this index moves, the pay of millions of workers moves with it.

CPI = (Cost of fixed basket in current year ÷ Cost of the same basket in base year) × 100

Inflation (%) = (Iₜ − Iₜ₋₁₂) ÷ Iₜ₋₁₂ × 100. Here Iₜ is this month's index and Iₜ₋₁₂ is the index for the same month last year [2].

Explanation

How the index is built

• Reference group: industrial workers' households. The index does not cover all consumers.
• Basket of commodities: a fixed set of goods and services that this group usually buys.
• Weights (how much each item counts) come from household consumption expenditure surveys.
• If an item takes a bigger share of the family budget, it gets a bigger weight.

• Food has the highest weight in CPI-IW (NCERT exercise).

• Retail prices: the prices workers actually pay in shops, not wholesale (bulk trade) prices.

• Prices come from 317 markets in 88 industrially important centres [5].

• Family budget method (NCERT): CPI = ΣWR ÷ ΣW.

• R (price relative) = (p₁ ÷ p₀) × 100. It shows how far one item's price has moved. p₀ is the base-year price and p₁ is the current price.
• W = the item's weight in the budget.
• Keeping base-year quantities fixed makes it a Laspeyres-type index (an index that uses base-year quantities as weights).

Worked examples

• Weighted price relatives (Class 11, Table 7.4):
• Items: food (W 35), fuel (10), cloth (20), rent (15), miscellaneous (20).
• ΣWR = 9,786.85 and ΣW = 100.
• CPI = 9,786.85 ÷ 100 = 97.86, so the cost of living fell by 2.14%.

• NCERT prints the food WR as 3,883.45. The correct value is 35 × 96.67 = 3,383.45, and only this value gives the printed total.

• Finding food's weight (Class 11, Q18):

• CPI = 125, food index = 120, index for all other items = 135. Let food's weight be w.
• 120w + 135(1 − w) = 125 → 135 − 15w = 125 → w = 2/3.
• So food makes up about 66.7% of the worker's basket.

How to read a CPI-IW number

• "CPI-IW (2001=100) is 277 in December 2014" means this:
• A worker spent ₹100 on the basket in 2001.
• The same basket cost ₹277 in December 2014.

• So prices of that basket rose 177% over those years.

• The index measures purchasing power, meaning whether the worker can still buy the same basket. It does not track what the worker actually bought.

• What makes it rise: food has the biggest weight, so jumps in food prices push CPI-IW up faster than most other items do.

Base revision and the linking factor

• Base changed from 2001=100 to 2016=100 in 2020 [4].
• Linking factor = 2.88 [4]. This number converts a new-series value into old-series terms.
• Example: a new-series index of 130 × 2.88 ≈ 374 on the old 2001 base.
• Why it matters: DA calculations can carry on smoothly even though the base changed.

In India

• Compiler: the Labour Bureau, Ministry of Labour and Employment. It releases the index monthly.
• Coverage: 317 markets in 88 industrially important centres [5].
• Current base: 2016=100, released in 2020, with a linking factor of 2.88 to the 2001 series [4]. The NCERT base is 2001=100, and the May 2017 value on that base was 278.
• Use:
• DA (an extra payment that makes up for rising prices) for government employees.

• Revision of industrial workers' wages [5].

• Other Labour Bureau indices:

• CPI-AL (agricultural labourers) and CPI-RL (rural labourers).

• Both moved from 1986-87=100 to 2019=100, with effect from the June 2025 index [6].

• NSO (MoSPI) indices:

• CPI-Rural, CPI-Urban and CPI-Combined moved to 2024=100, first released on 12 February 2026 [3].
• CPI-Combined, not CPI-IW, is the index the RBI uses for its 4% ± 2% inflation target under Section 45ZA of the RBI Act, 1934 [7].

Don't confuse with

• CPI-Combined (CPI-C): compiled by the NSO (MoSPI) on the 2024=100 base [3]. It measures headline retail inflation and is the RBI's target. CPI-IW is compiled by the Labour Bureau and is used for DA.
• CPI-AL / CPI-RL: also compiled by the Labour Bureau, but on the 2019=100 base [6]. They are used for agricultural and rural minimum wages, not for DA.
• CPI-UNME (Urban Non-Manual Employees): formerly compiled by the CSO. It has been discontinued and replaced by CPI-Urban. It was never used for industrial workers' DA.
• WPI: uses wholesale (bulk trade) prices and leaves out services. CPI-IW uses retail prices. Retail price = wholesale price + traders' margin, so the two indices can move differently.

Prelims Hooks

• CPI-IW is compiled by the Labour Bureau, not the NSO. A common trap swaps it with CPI-Rural, CPI-Urban and CPI-Combined, which the NSO compiles.
• Base: 2016=100, released in 2020. The linking factor is 2.88 to the old 2001=100 series [4].
• Prices come from 317 markets in 88 industrially important centres [5].
• CPI-IW → DA of government employees and industrial wages. CPI-AL → agricultural minimum wages. CPI-C → RBI's inflation target.
• Food has the highest weight in CPI-IW. The NCERT family budget formula is CPI = ΣWR ÷ ΣW.
• CPI-IW is a cost-of-living index built on retail prices and a fixed base-year basket, which makes it a Laspeyres-type index.

Mains Points

• Wage indexation and fairness (GS-II/GS-III):
• A worker's basket is mostly food, so a general index would understate how much their cost of living has risen.
• A group-specific index like CPI-IW links DA to the prices these workers actually face.

• This protects their real wages (wages adjusted for prices).

• Old bases distort pay:

• A basket from an old survey gives too much weight to items people now buy less of.
• Moving from 2001 to 2016 in 2020 [4], and using a linking factor for continuity, brings DA closer to current spending.

• The reform path is regular 3–5 year rebasing tied to HCES data, as MoSPI plans for the national CPI [2], and bringing the Labour Bureau indices in line with that cycle.

• Many CPIs, weak comparability:

• CPI-IW (2016), CPI-AL/RL (2019) and CPI-C (2024) have different bases and compilers [4][6][3].
• This helps each index serve its own purpose, such as wages or monetary policy.
• But it makes comparing inflation across groups harder, which is an argument for aligning bases and methods.

Related concepts

• Consumer Price Index
• Basket of commodities
• Retail prices
• CPI for Agricultural Labourers
• CPI for Rural Labourers
• CPI for urban non-manual employees
• CPI-Rural and CPI-Urban
• CPI-Combined
• Consumer Food Price Index

Read more

• The consumer price index family in India