The term "blue collar workers" refers to those workers who do manual labor. This is as opposed to the term "white collar workers," which refers to those workers who do work that uses their brains more than their physical strength.
This term originates from the idea that a person who was going to work with their hands would not wear white shirt because it would get dirty and was often assigned a blue uniform. By contrast, someone working in an office would be able to wear such a shirt.
In general, blue collar jobs are less prestigious than white collar jobs and blue collar workers are not as well-paid.
This is a term that refers to people involved in manual labour and earn daily wages. They are at the lowest rung of the job- status hierachy. The use of 'blue' probably comes from the practice of most of these vocations using blue uniforms to demarcate their workers from others in the hierarchy. For example the 'white collar' workers are educated professionals working in offices at desks and on computers. The colour code again indicates their regular attire to be mainly white.
In recent times, there have been references to green collars who are people working in the environment industry, brown and grey collars who would be the technician level workers who fix your phones or computers etc.
With an influx of new job profiles now a days, new terms are being coined by the day. For example, the newly minted term 'cyber coolies' refers to people working in the Business Process Outsourcing (BPO) industry. Coolies would indicate 'blue collar' work but it is to do with computers. So could they be then called grey collars? Worth considering!
blue collar jobs are opposite to white collar jobs, it includes field work as well as other technical work in physical labour is involved.such jobs are not limited to offices in such jobs workers often gets dirty and when there are chances of getting dirty it is obvious he will not wear white shirts