The Department for Promotion of Industry and Internal Trade (DPIIT) on Monday released a revised series of the Wholesale Price Index (WPI) with 2022-23 as the new base year, replacing the existing 2011-12 series. Alongside the revised WPI, the government also launched new series of Output Producer Price Index (OPPI), Trial Input Producer Price Index (IPPI), and Service Producer Price Indices (PPI) for selected sectors.
The Office of the Economic Adviser said the move is aimed at modernising India’s inflation measurement framework and aligning it with international best practices. The transition from WPI to Producer Price Indices follows recommendations of the International Monetary Fund (IMF) and practices adopted by several advanced economies.
According to the government, the existing WPI series will continue to be released for five years alongside the Producer Price Indices before being discontinued, allowing sufficient time for users to shift to the new framework.
The revised WPI basket has been expanded from 697 items to 957 items, reflecting changes in the economy and production patterns. Renewable energy sources such as solar and wind power, along with nuclear electricity, have been included under the electricity category. Crude petroleum and natural gas have also been shifted from the Primary Articles group to the Fuel and Power category to improve the tracking of energy prices.
The new series introduces methodological improvements, including the use of Gross Value of Output (GVO) for assigning weights, a short-term formulation method for compiling elementary indices, and a targeted mean imputation approach for handling missing price data.
For May 2026, provisional estimates showed Wholesale Price Index inflation at 9.68 per cent on a year-on-year basis, up from 8.26 per cent in April. The index for all commodities stood at 109.9 in May compared to 108.8 in the previous month. Fuel and Power recorded the highest inflation at 30.33 per cent, followed by Manufactured Products at 7.48 per cent and Primary Articles at 4.99 per cent.
The government identified mineral oils, crude petroleum and natural gas, chemicals and chemical products, and basic metals as the major contributors to wholesale inflation during April and May 2026. The WPI Food Index rose by 4.49 per cent year-on-year in May, compared with 3.11 per cent in April.
The newly introduced Output Producer Price Index showed that the all-commodity OPPI increased to 109.6 in May from 108.6 in April. Manufactured products, agriculture, mining and quarrying continued to drive producer-level price movements.
The Trial Input Producer Price Index, currently being published on an experimental basis for the manufacturing sector, stood at 104.9 in May 2026. The government said the trial phase will help assess data quality and gather stakeholder feedback before wider adoption.
The Office of the Economic Adviser has also introduced Service Producer Price Indices for seven sectors in the first phase, including banking, securities transactions, insurance, management of pension funds, railways, air passenger transport and telecommunications. These indices will be released quarterly. For the fourth quarter of FY 2025-26, the Securities Transaction Service Price Index rose to 91.7, while the Railway Service Price Index increased to 103.3.
