Industries are divided into three broad categories namely primary, secondary and tertiary.
(i) Primary Industries They include all those activities which are connected with extraction and production of natural resources and reproduction and development of living organisms, plants, etc.
These industries are subdivided into two types
(a) Extractive Industries They are involved in extraction of products from natural resources. For example, wood from forests, fish from rivers and minerals from earth.
(b) Genetic. Industries They include activities connected with rearing and breeding of animals and birds and growing plants. For example, agricultural activities, animal husbandry, dairy farming, poultry farming, etc.
(ii) Secondary Industries They are concerned with the further processing of materials which have already been extracted at the primary stage. For example, the mining of an iron ore is a primary industry but manufacturing of steel from that iron is secondary.
Secondary industries may be of two types
(a) Manufacturing Industries They convert raw materials into finished products like cotton into textiles, wood into furniture or iron into steel.
(b) Construction Industries Activities concerned with the construction of houses, roads, bridges, dams, seaports, etc belong to the category of construction industies. The main feature of these activities is that the output consists of immovable goods.
(iii) Tertiary Industries They are concerned with providing support services to primary and secondary industries as well as activities related to trade. For example, transportation, banking, insurance, warehousing, etc.