In a major overhaul in the way producer-level inflation is measured in India, the government will gradually replace the Wholesale Price Index (WPI) with a more comprehensive Producer Price Index (PPI).The Department for Promotion of Industry and Internal Trade (DPIIT) will release the revised WPI series with a new base year of 2022-23 on June 15, alongside the country's first Output Producer Price Index (OPPI), Trial Input Producer Price Index (IPPI) and Service Producer Price Index (Service PPI) covering seven key services, officials said on Tuesday.Addressing the media, Principal Economic Adviser Praveen Mahto said the transition would be gradual, with both WPI and PPI running in parallel for five years before WPI is eventually discontinued."Considering the wide usage of WPI in price escalation clauses, this index will be released for five years from the date of release of the revised series along with PPI and will be discontinued thereafter," the commerce and industry ministry said in a statement, PTI quoted.Mahto said the five-year transition period would provide sufficient time for users to shift to the new framework. After that, the PPI is expected to replace WPI.The move aligns India with global practices followed by advanced economies and recommendations of the International Monetary Fund (IMF).Unlike WPI, the new framework will track output prices, input costs and service-sector inflation, providing a more detailed picture of producer-level price movements and inflation transmission across industries."The availability of both Output PPI and Input PPI provides a better understanding of the price movements of output items vis-à-vis the input items used in an industry," Mahto said."It also explains how inflation experienced by producers on input items is passed through the output being produced."The Service PPI will initially cover seven sectors — Banking, Securities Transaction, Insurance, Management of Pension Funds, Railways, Air Passenger Services and Telecom.Mahto said additional services would be included in future phases, subject to data availability.The DPIIT said WPI and Output PPI will be released monthly, with the first publication for May 2026 along with back-series data from April 2023 to April 2026. The Trial Input PPI for manufacturing will be released on an experimental basis from March 2026 onwards."This would enable the department to examine the data quality and also receive feedback from stakeholders and users," the ministry said.Service PPI, which will be compiled quarterly, will be released for the fourth quarter of FY26 along with historical data from Q1 FY24 to Q3 FY26.The revised WPI basket has also undergone significant changes. According to Dilip Kumar Sinha, Deputy Director General in the Office of Economic Adviser, the number of items covered has increased from 697 to 957.New energy sources such as solar, wind and nuclear power have been added, while crude petroleum and natural gas have been shifted from the primary articles category to the fuel and power group.Sinha said the reclassification would improve alignment since the fuel and power category already includes coal, electricity and petroleum products.WPI, Output PPI and Service PPI will be compiled using basic prices, excluding taxes and trade margins, while Input PPI will be calculated using purchaser prices because industries buy inputs from the market.India first introduced WPI in 1942 with 1939 as the base year and has revised the series seven times since then. The current WPI series, based on 2011-12, was launched in May 2017.The overhaul comes at a time when wholesale inflation remains under pressure. Wholesale price inflation accelerated to a 42-month high of 8.3 per cent in April, driven by higher energy prices following disruptions linked to the West Asia conflict.