Union

No one can stop formation of union provided that all aspects of forming union is complied with. Please check the Trade Unions Act for more information/ details. 

No. It can't.  But quite often it happens.  Fill up the union registration application and complete all the details with supporting documents and file it before the Registrar of Trade Unions.  If within the reasonable time, the union has not been registered without valid reason, then file a writ case before the High Court for registration of union.