To address your query, there are a few points that we need to note:
1. Whether the contract is a genuine contract or a "sham"?
2. If the contract is a sham, the next question is how many days these workmen were employed by the principal employer in his factory?
3. Once the "supervision and control" aspect is established, you (your organization) will be construed to be his employer.
4. Once the Employee–Employer relationship between you and the contractor labor is established, and you check a person out who has put in 240 days of work, it will be construed as retrenchment. Therefore, [sec 2 (oo)] of the I.D. Act will apply to you.
5. Following are the excerpts from the ID Act:
6. Once they prove that they have worked with the contractor for a minimum of 240 days, the court may hold and an order may be passed for reinstatement (with or without back wages).
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Industrial Disputes Act, 1947
25B. Definition of Continuous Service
For the purposes of this Chapter:
(1) A workman shall be said to be in continuous service for a period if he is, for that period, in uninterrupted service, including service which may be interrupted on account of sickness or authorized leave or an accident or a strike which is not illegal, or a lock-out or a cessation of work which is not due to any fault on the part of the workman.
(2) Where a workman is not in continuous service within the meaning of clause (1) for a period of one year or six months, he shall be deemed to be in continuous service under an employer:
(a) For a period of one year, if the workman, during a period of twelve calendar months preceding the date with reference to which calculation is to be made, has actually worked under the employer for not less than:
(i) One hundred and ninety days in the case of a workman employed below ground in a mine; and
(ii) Two hundred and forty days, in any other case;
(b) For a period of six months, if the workman, during a period of six calendar months preceding the date with reference to which calculation is to be made, has actually worked under the employer for not less than:
(i) Ninety-five days, in the case of a workman employed below ground in a mine; and
(ii) One hundred and twenty days, in any other case.