Labour license is required to keep and employ labours within a company. Especially it becomes mandatory, if you are a contractor or petty contractor.
Labour license is in reality a registration that a contractor has to take with Labour Department for keeping or employing labour within his company. But it does not mean, others do not have to take Labour License.
A labour contractor who employs labours and do works under principal employer is required to take labour license from labour department of the state. Any contractor who does not work under any employer but employs labours has to get contractor registration from either road construction department or building construction department of the state. Only after this, he can apply for getting labour license to keep labours for his works.