Amit, you can ask Dr. Renato Westermeier ([email protected]). He works in your area, probably can help you to determine at least the Family if not the Genus.
Agreeing with Dr. Rao and Dr.Reddy but I think it is Grateloupia lithophila Børgesen 1938, If the thallus shows the following characteristics:
Plant in dense tufts on hard substratum; thallus flat simple or irregularly divided, 10 - 15 cm long, 0.5 - 2 cm broad, linear lanceolate tapering from the middle to both the ends, sinuate and undulating; upper ends of the fronds, truncate becoming more or less broadly rounded; proliferation arising from upper end and from the sides of fronds; section of thallus with a central medullory and peripheral cortical potion; cortical portion of short dichotomously branched filaments; cells of medullary region adjoining cortex, about the same size as cells of cortex, regular in shape; tetrasporangia are celled, scattered over the surface of the thallus; cystocarp sunk in the thallus.
You may check Algaebase for further details about the species. It is a bit hard to say about species from the image, more particularly iwhen the specimen not spread properly.