India's industrial production expanded at a slower pace of 4.9% in April due to tepid growth in the energy sector amid the West Asia crisis, according to official data released on Monday (June 1, 2026).This is the first data released after the revision of the base year to 2022-23 and the rejigging of the index constituents. The factory output, measured in terms of the Index of Industrial Production (IIP), expanded by 5.7% in April 2025.The growth rate was 3.2% in March 2026. "Driven by strong growth of 6.2% in the manufacturing sector, Index of Industrial Production (IIP) records 4.9% growth in April 2026," the Ministry of Statistics & Programme Implementation (MoSPI) said in a statement.The growth rates of the four sectors — mining & quarrying, manufacturing, electricity & gas supply, water supply, sewerage and waste Management — for April 2026 stood at (-) 5.15%, 6.2%, 4.9% and 6.6%, respectively, it said.The quick estimate of IIP stands at 118.9 against 113.1 in April 2025. The MoSPI has revised the base year of the IIP from 2011-12 to 2022-23. The revised basket consists of 1,042 products mapped to 463 item groups, including 120 new item groups.The base year revision exercise was undertaken under the aegis of the Technical Advisory Committee for Base Year Revision of the All India Index of Industrial Production (TAC-IIP).The committee's report was released on May 25, 2026, laying the foundation for a more robust, relevant, and comprehensive measure of industrial production in India. This is the 10th revision of the base year for IIP. The first IIP was prepared with a base year 1937.According to the MoSPI, the new IIP series provides greater granularity with separate indices for the generation of electricity through renewable and non-renewable, gas supply, fuel minerals, metallic minerals and non-metallic minerals, water supply, sewerage and waste management.In the new IIP series, a total of 120 new item groups have been added, including cards with a magnetic stripe (debit card, credit card), CCTV camera, articles of non-woven textiles, parts of aircraft and spacecraft, stents, and vaccine.Also, 64 item groups, including kerosene, fluorescent tubes and CFLs, tubes for bicycle/ tricycle/ rickshaw/LMV tyres, printing machinery, and sewing machines, have been dropped.An expanded item basket improves representativeness, captures diversification in industrial production, and reflects emerging industrial products and technologies, MoSPI said, adding that the IIP will be released every month with a time lag of 28 days from the reference month.Briefing the media after the release of the index, MoSPI Secretary Saurabh Garg said the new IIP series plugs gaps in the previous batch, and has included minor mineral.Also, greater weightage has been assigned to plastic, rubber, and automobiles in the new series, he informed. "I would also like to highlight that the data gaps that we had in the previous IIP we have filled that," the secretary said, and explained about the new additions in the series, including gas supplies, minor minerals and rare earth minerals.According to the new IIP series, within the manufacturing sector, 17 out of 23 industry groups recorded a positive growth in April 2026 over April 2025. The top three positive contributors during April 2026 were: 'manufacture of motor vehicles, trailers and semi-trailers' (12.7%), 'manufacture of electrical equipment' (19.2%), and 'manufacture of machinery and equipment n.e.c' (12.9%), the IIP data showed.Growth rates of IIP, as per use-based classification, in April 2026 over April 2025 were 0.8% in primary goods, 16% in capital goods, 7.7% in intermediate goods, 7.1% in infrastructure/ construction goods, 4.3% in consumer durables and 2.8% in consumer non-durables.Based on use-based classification, top 3 positive contributors to the growth of IIP during April 2026 were intermediate goods, capital goods and infrastructure/ construction goods.In the new series, weights have been revised compared to the series with a base year of 2011-12. The weight of the 'mining and quarrying' has been reduced from 14.372 in the old series to 11.053 in the new series, and in the case of 'manufacturing' from 77.633 to 76.062.In the case of 'electricity and gas supply', the weight has been increased from 7.995 to 10.865. Weigh of 2.020 has been assigned to 'water supply; sewerage and waste management', a new entry into the IIP series.MoSPI officials informed that, as part of the old series, the Ministry was also working with the States. About 24 States are already preparing their State-level IIPs.The MoSPI is following up with the remaining States, and they too should start compiling their indices.Commenting on the new series, Dipti Deshpande, Principal Economist, Crisil, said the expanded IIP basket provides a more comprehensive view of industrial activity and better captures emerging sectors. "Industrial growth as measured by the Index of Industrial Production (IIP) accelerated to 4.9% in April, from 3.2% in March, driven by stronger growth in manufacturing and electricity production. Domestic demand held up, as evident from auto sales, retail credit, electricity demand, and others, despite headwinds from the West Asia conflict," Ms. Deshpande said.Aditi Nayar, Chief Economist at ICRA, said the new IIP series has factored in several changes, including a revision of the item basket, changes in sectoral weights, and an increase in the number of reporting factories. "Interestingly, as per this, industrial output expanded at a relatively higher pace in FY2024 and FY2025 than previously estimated, with the manufacturing sector in particular reporting much higher growth rates in both these years."This could lead to some upward revision in the GDP estimates for these years, when the revised data for the same is released later this week," Ms. Nayar said.