The Index of Eight Core Industries (ICI) is a high-frequency macroeconomic indicator and a production volume index that measures the combined and individual performance of eight fundamental sectors of the Indian economy. It is compiled and released monthly by the Office of the Economic Adviser (OEA), which falls under the Department for Promotion of Industry and Internal Trade (DPIIT) in the Ministry of Commerce & Industry.
The ICI was created to track the output of sectors considered the backbone of industrial activity, providing a timely signal of the country's economic health and industrial momentum. Its mechanism involves calculating a weighted arithmetic mean of the production quantity relatives using a Laspeyres-type volume index formula. The current base year for the index is 2011-12. The eight industries included are Coal, Crude Oil, Natural Gas, Refinery Products, Fertilizers, Steel, Cement, and Electricity.
The ICI is intrinsically connected to the broader Index of Industrial Production (IIP), as the eight core industries collectively account for 40.27% of the total weight of items in the IIP. This significant weight makes the ICI a reliable leading indicator for the overall industrial sector's performance. A key recent change involved the revision of the base year from the previous 2004-05 to 2011-12. Following this revision, Refinery Products now hold the highest weight at 28.04%, a change from the previous structure where Electricity had the highest weightage.