Mr Venkatesh it seems you are representing Principal Employer. You have awarded contract of costruction to a contractor and there is an agreement between your company and the contractor . The contractor has undertaken to produce given result for you. If you have not allowed him to engage sub contractor in your agreement then contractor has to obtain licence under Contract Labour Act. The record of sub contractors has to be maintained by the main contractor as if the workers employed by main contractor ignoring the existence of the sub contractor.