Industry is often classified into three sectors: primary or extractive, secondary or manufacturing, and tertiary or services. Some authors add quaternary (knowledge) or even quinary (culture and research) sectors.
Industries can be classified on the basis of raw materials, size and ownership and time.
- Raw Materials: Industries may be agriculture based, Marine based, Mineral based, Forest based….
- Size: It refers to the amount of capital invested, number of people employed and the volume of production.
- Ownership: Industries can be classified into private sector, state owned or public sector, joint sector and co-operative sector