Dear Rekha,
When the appropriate Government under the Minimum Wages Act,1948 which fixes the minimum wages is a State Government for any employment, relatively it is bound to vary from the rates of other States.. Therefore, when an industry shifts its location to some other State where the rates of minimum wages are comparatively less or transfer some of its employees to such a State, it cannot unilaterally reduce the existing higher rates of wages on par with the lower rates fixed by the latter State without the consent of the employees concerned under a bilateral settlement or without issuing a 21 day notice u/s 9-A of the Industrial Disputes Act,1947.
Though overall or gross salary remains the same, certainly when the basic is less, it will have cyclical impact on indirect benefits like bonus, gratuity, contribution to EPF etc.