Explanation:

 The Index of Industrial Production (IIP) is an index for India which details out the growth of various sectors in an economy such as mining, electricity and manufacturing. The all India IIP is a composite indicator that measures the short-term changes in the volume of production of a basket of industrial products during a given period with respect to that in a chosen base period. It is compiled and published monthly by the Central Statistical Organisation (CSO) six weeks after the reference month ends. The level of the Index of Industrial Production (IIP) is an abstract number, the magnitude of which represents the status of production in the industrial sector for a given period of time as compared to a reference period of time. The base year was at one time fixed at 1993–94 so that year was assigned an index level of 100. The current base year is 2004–2005.
The Eight Core Industries comprise nearly 38 % of the weight of items included in the Index of Industrial Production (IIP). These are Electricity, steel, refinery products, crude oil, coal, cement, natural gas and fertilisers.