Man is an active and wise creature who performs many activities while being influenced by physical and cultural environments. Since these environments are different in different regions, so human economic activities also change along with the changes in region.

Economic activities done by man have been changing since the pre – historic age to upto the present. The means of earning human livelihood and economic activities are classified into five categories. The classification has been done on the basis of increasing distance from land and its natural resources.

1. Primary Occupations: The occupations in which man directly uses naturally recurring resources like – land, water, vegetation and minerals to fulfil his needs are known as primary occupations. These types of occupations are directly associated with the status of natural environment. These occupations involve production of food and raw materials, hunting, gathering forestry products, agriculture, fishing, wood cutting, animal husbandry, mining, etc. are primary occupations.

2. Secondary Occupations: Instead of being used directly in secondary occupations, naturally available resources are first of all refined and converted into more useful and valuable products. Secondary occupations include manufacturing, processing and production activities. Making steel from iron ore, flour from wheat, cotton textile from ’cotton, sugar from sugarcane, furniture and paper from wood are some of fine examples of secondary occupations.

3. Tertiary Occupations: All personal and commercial direct servies to communities are included in tertiary occupations. It is also known as “Service Category”. Following are the examples of this type of occupation:

• Transportation 
• trade and commerce 
• communications 
• all the services including banking, insurance, tourism, etc.,

4. Quaternary Occupations: This class is related to information based and research and development based services. Jean Gottman includes intangible (indirect) services in the category of quaternary occupations. More than half of workers in developed countries are employed in these knowledge based occupations. Information, researches and inventions, hospitals, theatre, accounts work, governance, legal and technical advisors are the examples of quaternary occupations.

5. Pentanary Occupations: Pentanary or fifth level occupations include those services which are focussed on creation of new contemporary ideas and explanation of their re – organisaton, explanation of data and their application and evaluation of new technology. These occupations are also the sub-classes of tertiary occupations, in which subject specialists, decision makers, consultants and policy makers are included.