On 4 November 2026 the Union Cabinet approved VISTAR (Viksit Bharat Initiative for Statistical Transformation, Analytics & Research), a ₹4,371.10 crore scheme for 2026-27 to 2030-31. It funds 59 surveys against 43 earlier and the 8th Economic Census. The same day, the Ministry of Statistics released the detailed publications of the Annual Survey of Industries (ASI) 2024-25. Both stories are about the machinery that produces India's numbers. The CDS paper asks who compiles which index, on what base year, covering what? Several answers changed in 2026.
Who Compiles What: The Index Map
By Hitendra Deswal · Economics faculty, The Cavalier
India has no single "inflation number". It has a family of indices, each built by a different office. Learn this table as a set, because most questions test one row.
| Series | Compiled by | What it measures | Base year now |
|---|---|---|---|
| CPI (Consumer Price Index, Combined) | National Statistical Office (NSO), MoSPI | Retail prices paid by households, goods and services | 2024 = 100 (was 2012) |
| WPI (Wholesale Price Index) | Office of the Economic Adviser, DPIIT, Ministry of Commerce and Industry | Wholesale prices of goods only | 2022-23 (was 2011-12) |
| IIP (Index of Industrial Production) | NSO, MoSPI | Volume of output of mining, manufacturing, electricity and water | 2022-23 (was 2011-12) |
| GDP (and the GDP deflator) | NSO, MoSPI | Value of all goods and services produced | 2022-23 (new series released 27 Feb 2026; was 2011-12) |
| ASI (Annual Survey of Industries) | NSO, MoSPI | Structure, output, employment and value added of registered factories | Reference year 2024-25 |
| CPI-IW (Industrial Workers) | Labour Bureau, Ministry of Labour | Retail prices for factory workers; used for dearness allowance | 2016 = 100 |
CPI, IIP, GDP and ASI come from MoSPI; WPI and the core index from DPIIT (Commerce). The RBI compiles none of them.
VISTAR aims to keep the numbers current, with district-level estimates, State-level IIP and mobile-phone and e-commerce data alongside surveys. The ASI shows what such data reveals: in 2024-25 the manufacturing corporate sector's gross value added grew 9.28%, and Maharashtra, Gujarat, Tamil Nadu, Karnataka and Uttar Pradesh produced over 54% of it.
How an Index Number Is Built
An index number shows how a group of prices (or quantities) has changed against a base year, whose index is set to 100. Fix a basket of items, give each a weight equal to its importance in spending, and track the weighted prices. An index of 112 means the basket costs 12% more than in the base year.
Three groups, with base-year spending shares as weights and current price indices (base = 100).
That second line is what happened in 2026. As incomes rise, households spend a smaller share on food (Engel's law), so weights must be cut or the index keeps measuring a country that no longer exists. Hence every index is rebased every few years, and MoSPI publishes linking factors to join old and new series.
Inflation = (new index − old index) ÷ old index × 100. An index moving from 125 to 150 is 20% inflation, not 25. And if inflation falls from 6% to 5%, prices are still rising, only more slowly (disinflation). Only a fall in the price level itself is deflation.
CPI: The New 2024 Series, Headline and Core
The CPI is the index you hear on the 12th of every month. MoSPI released the new series with base 2024 = 100 on 12 February 2026, with January 2026 as the first reading (2.75%). It replaced the 2012 series. The changes are structural, not cosmetic.
| Feature | Old series (2012 = 100) | New series (2024 = 100) |
|---|---|---|
| Weights from | Consumption survey of 2011-12 | Household Consumption Expenditure Survey 2023-24 |
| Groups (divisions) | 6 | 12, following the international COICOP 2018 classification |
| Items in the basket | 299 | 358 |
| Weight of food and beverages | 45.86% | 36.75% |
Prices for the new series are gathered by the NSO's Field Operations Division on a weekly roster from 1,407 urban markets (including online markets) and 1,465 villages across all States and Union Territories.
The CPI is published as General (all items), the Consumer Food Price Index (CFPI), and rural, urban and combined series. In July 2026 combined inflation was 4.45% and food inflation 5.52%; see our report on the CPI on the new 2024 base.
Headline vs core. Headline inflation is the all-items CPI. Core inflation removes food and fuel, which swing with the weather and world oil prices. The RBI's tool, the interest rate, works on demand; it cannot bring rain or cut onion prices after a crop failure. So the bank watches core to see whether price pressure is demand-led. Volatility is real: tomato inflation swung from +31.92% in June 2026 to −4.59% in July. For a poor household food is most of the budget, so core understates the inflation it feels.
The Labour Bureau's CPI-IW (2016 = 100) is the index behind the dearness allowance of central government employees. The causes and control of inflation are in our notes on inflation; this article stays with measurement.
WPI, PPI and Why They Differ from CPI
The WPI measures the average change in wholesale prices of goods. Its three groups carry very different weights in the 2022-23 series.
| WPI group | Weight, 2011-12 series | Weight, 2022-23 series |
|---|---|---|
| Manufactured products | 64.23 | 63.13 |
| Primary articles | 22.62 | 22.76 |
| Fuel and power | 13.15 | 14.11 |
The WPI is being replaced for three reasons.
- Multiple counting. Steel can be recorded at several wholesale stages, so intermediate goods are counted more than once.
- Taxes and margins. WPI prices can include indirect taxes and trade margins, which reflect policy and distribution, not production cost.
- No services. Services are over half the economy, but the WPI ignores them.
The answer is a Producer Price Index (PPI). It records the price the producer receives at the factory gate, excluding indirect taxes and trade margins, and can cover services. With the WPI revision to the 2022-23 base, the Office of the Economic Adviser began publishing an Output PPI, a trial Input PPI and a Services PPI for seven services, including banking, insurance, railways and telecom. The WPI is to run alongside the PPI for about five years before it is discontinued. Our report on WPI and the shift to a Producer Price Index covers the July 2026 numbers.
The baskets differ. The WPI is mostly manufactured goods and fuel (fuel and power inflation was 20.05%), while the CPI is dominated by food, housing and slow-moving services. Retailers also absorb or delay wholesale cost rises.
IIP, the Core Index and ASI: Measuring Output
Prices tell you about inflation; output indices tell you whether the factories are running. The IIP measures the volume of production, and its base moved from 2011-12 to 2022-23 in June 2026.
- Four sectors, not three. The old IIP had mining, manufacturing and electricity; the new one adds water supply, sewerage and waste management, and electricity becomes electricity and gas supply. Manufacturing carries roughly three-quarters of the weight.
- Wider basket. Products rise from 839 to 1,042, with rare earth minerals and renewable energy covered for the first time.
The IIP also has a use-based classification: primary, capital, intermediate and infrastructure/construction goods, and consumer durables and non-durables. Capital goods growth proxies investment demand. July 2026 growth was 6.7% (quick estimate); see our report on the new IIP series.
The Index of Eight Core Industries (ICI) is a faster cousin released by DPIIT around the 20th. The classical eight are coal, crude oil, natural gas, refinery products, fertilisers, steel, cement and electricity; on the 2022-23 base iron ore is added. Electricity, refinery products and steel make up about 71%. As upstream inputs, they lead the IIP. See our core industries report.
Monthly indices are quick estimates. The Annual Survey of Industries is the detailed survey of registered factories: capital, employment, wages, output and value added by industry and State. It feeds the national accounts and the IIP's manufacturing weights. In ASI 2024-25, factories with plant and machinery up to ₹5 crore were 78.69% of all factories but gave only 17.61% of net value added.
GDP Deflator and the RBI's Yardstick
The GDP deflator is the broadest price index. It is the ratio of nominal GDP (current prices) to real GDP (base-year prices):
An economy produces only bread. In the base year it makes 100 units at ₹10. The next year it makes 110 units at ₹15.
The deflator differs from the CPI in three ways. It covers everything produced, not just what a consumer buys; it excludes imported goods, which the CPI includes; and its weights change with the structure of production, while CPI weights are fixed. Its growth is an inflation measure. The GDP series is explained in our notes on national income.
Finally, the target that gives the CPI its power. India follows flexible inflation targeting, written into the RBI Act, 1934 in 2016. On 25 March 2026 the government, in consultation with the RBI, retained 4% CPI inflation with a band of ±2% (2% to 6%) for April 2026 to March 2031. The six-member Monetary Policy Committee (three from the RBI, three from the government) sets the repo rate against it; see our monetary policy notes.
How UPSC Has Asked It: Past Papers Solved
These are actual CDS questions since 2020: weights, definitions and quick index arithmetic.
Consider the following statements regarding weightage of different articles in Wholesale Price Index (WPI): 1. Fuel and power have higher weightage in WPI than that of primary articles. 2. Weightage of manufactured products in WPI is higher than that of fuel and power. Which of the statements given above is/are correct?
(a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2
Answer: (b). Manufactured products carry over 60%, primary articles about 22 to 23%, and fuel and power 13 to 14%. Statement 1 reverses the last two.
Which of the following statements is/are correct? 1. GDP deflator captures the average price of an unchanging basket of commodities that constitutes the GDP of the country. 2. GDP deflator can be used to measure the real GDP of the economy but not the inflation rate.
(a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2
Answer: (d). Both are wrong. The deflator's basket is the whole of GDP and changes as production changes. And it is a price index, so its growth is an inflation measure.
If the price index increased from 100 in 2021 to 110 in 2022 to 132 in 2023, then the rate of inflation is:
(a) 10% (b) 32% (c) 20% (d) Cannot be determined
Answer: (c). (132 − 110) ÷ 110 = 20%. Option (b) is the rise since 2021 and (a) the 2022 rate. Divide by the previous year's index.
Core inflation is:
(a) CPI headline inflation minus all non-food items (b) WPI inflation minus all food and non-food items (c) CPI headline inflation minus food and energy items (d) WPI inflation minus food and energy items
Answer: (c). Core inflation is a CPI concept that leaves out volatile food and energy items. Options (b) and (d) use WPI.
The Department for Promotion of Industry and Internal Trade (DPIIT) has revised the base year index of Eight Core Industries having a combined weight of about 40.27 percent in the Index of Industrial Production. Which one of the following is not one of the Eight Core Industries?
(a) Coal (b) Refinery products (c) Rubber products (d) Cement
Answer: (c). Rubber products are not among the eight (coal, crude oil, natural gas, refinery products, fertilisers, steel, cement, electricity).
As per the use-based classification of the Index of Industrial Production (IIP), the maximum weight has been assigned to
(a) primary goods (b) intermediate goods (c) consumer durables (d) consumer non-durables
Answer: (a). In the 2011-12 series the weights were primary goods 34.05%, consumer non-durables 15.33%, intermediate goods 17.22% and consumer durables 12.84%, so primary goods were the largest by a wide margin.
Most index questions test weights, compiler or arithmetic. Know the largest group in each index (manufactured products in WPI, primary goods in the old IIP, food in CPI) and divide by the earlier year.
Practice MCQs (with answers)
- The Consumer Price Index (Combined) is compiled by the
- Office of the Economic Adviser, DPIIT
- National Statistical Office, MoSPI
- Reserve Bank of India
- Labour Bureau
- Which statement about the Wholesale Price Index is correct?
- It covers goods and services
- It is compiled by the NSO
- It covers goods only
- It measures retail prices paid by households
- A price index rises from 125 in one year to 150 in the next. The rate of inflation is
- 20%
- 25%
- 50%
- 15%
- In the CPI series with base 2024 = 100, compared with the 2012 series, the weight of food and beverages has
- stayed unchanged
- risen because of vegetable price spikes
- risen with the addition of online items
- fallen to about 36.75%
- The main advantage of a Producer Price Index over the WPI is that it
- measures retail prices
- includes only imports
- is compiled by the RBI
- records factory-gate prices without taxes and trade margins, and can cover services
- On the 2022-23 base, the IIP covers how many sectors?
- Four
- Three
- Five
- Six
- The GDP deflator is calculated as
- real GDP ÷ nominal GDP × 100
- nominal GDP − real GDP
- nominal GDP ÷ real GDP × 100
- CPI ÷ WPI × 100
- India's inflation target, retained until March 2031, is
- 4% (±1%) on WPI
- 4% (±2%) on CPI
- 4% (±2%) on WPI
- 2% to 4% on the GDP deflator
1-b, 2-c, 3-a, 4-d, 5-d, 6-a, 7-c, 8-b. Q3: (150 − 125) ÷ 125 = 20%, not 25. Q4: the fall (45.86% to 36.75%) reflects Engel's law, not price spikes. Q8: the target is on CPI, not WPI.
Quick Revision
- Compilers: CPI, IIP, GDP, ASI = NSO. WPI and core industries index = Office of the Economic Adviser, DPIIT. CPI-IW = Labour Bureau.
- Base years: CPI 2024 = 100 (HCES 2023-24 weights, 12 groups, 358 items, food 36.75% from 45.86%). WPI, IIP, ICI and GDP 2022-23.
- WPI = goods only, mostly manufactured products (about 63%); to be replaced by PPI (factory-gate, no taxes or margins, covers services) after about five years.
- IIP now has four sectors and 1,042 products.
- Inflation = (new − old) ÷ old × 100. GDP deflator = nominal ÷ real × 100.
- Core = CPI less food and fuel. RBI target 4% ±2% on CPI, retained 25 March 2026 till March 2031.
Frequently asked questions
Which body compiles the CPI and the WPI in India?
The Consumer Price Index is compiled by the National Statistical Office under the Ministry of Statistics and Programme Implementation. The Wholesale Price Index is compiled by the Office of the Economic Adviser in the Department for Promotion of Industry and Internal Trade. The Reserve Bank of India compiles neither.
What is the current base year of the CPI, WPI and IIP?
The CPI now has the base 2024 = 100, introduced in February 2026. The WPI, the IIP and the new GDP series use 2022-23. The older series used 2012 for CPI and 2011-12 for the others.
Why is the WPI being replaced by a Producer Price Index?
The WPI covers only goods, can count a good more than once as it moves through wholesale stages, and can include indirect taxes and trade margins. A Producer Price Index records the factory-gate price without taxes and margins and can cover services. The WPI will run alongside it for about five years.
What is the difference between headline and core inflation?
Headline inflation is the change in the all-items CPI. Core inflation leaves out food and fuel, which are volatile and driven by supply shocks. Central banks watch it because interest rates act on demand.
What is the RBI's inflation target?
The government has retained a target of 4% consumer price inflation with a band of plus or minus 2%, that is 2% to 6%, for April 2026 to March 2031. The Monetary Policy Committee sets the repo rate with it in view.
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