The eight core sectors include – coal, crude oil, natural gas, refinery products, fertilizers, steel, cement and electricity. These industries have a major impact on general economic activities and also industrial activities. The core sector represents the capital base of the economy. These eight industries have a combined share of above 40% in the Index of Industrial Production (IIP). Source: https://timesofindia.indiatimes.com/business/india-business/core-sector-output-slows-down-to-4-5-in-july/articleshow/93905595.cms