The base year of IIP in India is 2011-12. The base year was changed from 2004-05 to 2011-12, in 2017. This change was done as a regular exercise by the former Central Statistics Office (CSO) functioning under the Ministry of Statistics and Programme Implementation. You can read about the Index of Industrial Production [UPSC Economy Notes] in the given link.
This was done to improve the representativeness and quality of indices, and capture the structural changes in the economy.
- Merger of NSSO and Central Statistical Office (CSO) to form National Statistical Office (NSO)
- Core Sectors of the Indian Economy