Contractor required separate registration in every state in which firm received work contract with material, labour and installation etc.??????

Reply— It is not compulsory to have registration in each state where contractor is supplying works contract service.  If contractor is willing to have a place of business in a state where he is supplying his services in respect of a contract, then only he is required to get registered in such state, otherwise he can provide such service as inter-state supply and can charge IGST on the same. 

It should be noted that contractor is not elgible to take ITC on local purchases from such state where he is working without registration.