Dear Shekhar,

While engaging workers there will be a contract with the contractor (who engages labour) that some specified conditions of service, like safety provisions, shift timings, intervals of rest, confidentiality matters etc, that the workers of the contractor should follow. 

You can engage contract labour only in such areas of operation which are not directly connected with the main business of the organisation. If you engage contract labour on work of perennial nature, that will be illegal. Housekeeping, security deployment etc are considered to be indirect operations and therefore, in such areas you can have contract labour. In a hospitality industry, for example, housekeeping in guest area is a core area of operation where you cannot have indirect labour. At the same time,for public area cleaning (admin office/ staff cafeteria etc) you can have contract labour. Similarly, in kitchen attached to restaurant you should have only direct labour but in staff kitchen you can have indirect / contract labour. 

Though late in responding but hope this helps  some seeking for clarification on this :- )

Regards,
 

P Thakur