I am not able to understand what sort of clarity Shivaji still needs.
Legal Rights of Trade Unions
Workers joining together and forming a trade union and getting it registered under the Trade Unions Act, 1926, is a legal right emanating from the fundamental right under Article 19(1)(c) of our Constitution. Contract laborers are not the lesser children of the law to be prevented from exercising this right just because such a union would be against the interests of the employers.
Contract Labor: An Overview
Contract labor is an indirect form of labor in which a third party, the contractor, comes into play between the actual beneficiary, the principal employer, and the contract laborers who are denied the legal benefits and rights of the regular employees performing the same work. If the work required to be performed is incidental or special in nature, there is no harm in engaging contract labor for such works through a contractor for the sake of delegation of effective supervision and control over the process and easy hire and fire as long as the work continues.
The ground reality is that even core activities are contracted out by way of outsourcing through third parties. Even though the ultimate beneficiary is the principal employer under this indirect employment system, the contract laborers cannot stake any claim against the principal employer because there is no direct employer-employee relationship between the two due to the presence of a third party, the contractor. That's why the enactment and enforcement of the Contract Labor (Regulation and Abolition) Act, 1970. It is better that you should go through the "Statement of Objects and Reasons" of the said Act.
Impact of Liberalization, Privatization, and Globalization (LPG)
After the advent of the so-called LPG, the system of contract labor has become ubiquitous in almost all industries, resulting in a paradigm shift in the pattern of employment, including Government departments. Even the CLRAA, 1970, has been in force for the last five decades, and despite certain regulatory measures introduced by the Act, experience shows that it remains a mere paper tiger to the extent that one can find almost 30% to 50% of contract laborers in every industry. Various High Courts and the Supreme Court of India have tightened the noose so far by their liberal interpretation of the provisions of the CLRAA, 1970, in several case laws. However, no industrial dispute against the principal employer would be maintainable regarding the permanency of the contract labor by the efflux of time unless it is proved that the contract is a sham, which is the ratio decidendi of the judicial pronouncements. Hence, the tactics of changing contractors while keeping the same set of contract laborers have been adopted by the industries for the sake of easy hire and fire as the economy becomes more market-driven. Even trade unions are also very skeptical about espousing the cause of contract labor, and the contract laborers are also scared of losing their existing contractual employment.