TECHNICAL FIELD The present invention is in relation to the field of material technology. In particular the present invention is related to a barrier material technology. The invention provides a high performance material in the form of layered film, comprising a graphene layer and a polymer layer which can act as an enclosure against air, moisture, oxygen and other gases. The layered film protects the product which it encloses from said gases abating degradation. The invention also provides a method for the preparation of said layered film. BACKGROUND Protection of various products sensitive to air, moisture, oxygen, light has become increasingly important in the present scenario to retard their deterioration. Many industries like; food, pharmaceutical, electronics which either use or market such sensitive products are governed by usage of suitable enclosures for their products to increase shelf life, reliability and the application. Such enclosures should be efficient in protecting the products from external influences which causes their deterioration. Specifically, in the electronics industry which comes up products in all walks of life, the use of organic electronic devices to produce high performing products has become imminent. The organic electronic devices like, organic light emitting diodes (OLEDs) and solar cells are sensitive to moisture and oxygen molecules as they seep past the protective layer over time and degrade the organic materials that form the core of these products. According to P. E. Burrows et al, Proc. SPIE 75, 4105, (2001), a water vapor transmission rate (WVTR) value of 1 x 10 g/m /day and oxygen transmission rate (OTR) 1x10" cm /m /day has become the informal standard for the organic light emitting diodes (OLEDs) to obtain a device lifetime of greater than 10,000 hours. For the said reasons, there has been intense interest in developing materials, commonly known as barrier materials with low permeabilities sustainable in accordance with the requirements of the industry. The ultra-low gas barrier film architecture that is commonly known consists of multiple layers of organic and inorganic thin films, called Vitex technology. Even though it has been shown as five dyads of organic/inorganic layers and provides a reduced water vapor transmission rate, the technique is complex and cost intensive. Multilayers of ALD (atomic layer deposition) and MLD (molecular layer deposition) for encapsulation are also good techniques but suffer from scalability. The processes are too complex and are of low throughput and are also difficult to apply to in case of organic devices. Graphene is an allotrope of carbon whose structure is a single planar sheet of sp-bonded carbon atoms, that are densely packed in a honeycomb crystal lattice; Nature materials, Vol 6, March 2007.Graphene is a single layer of graphite, with vibrant chemical, mechanical and electrical properties has been the cynosure in the recent times for harnessing its properties in various fields. Graphene has been found to be impermeable to gases including helium atoms; J.S. Bunt et al; Nano Letters, 2008, Vol. 8, No. 8, 2458-2462. There are reports wherein Graphene has been used in the preparation of materials which can reduce permeability, however none of the material reduce the permeability to the desired extent for replacing the barrier materials that are already in use. Some of the barrier materials involve constituents which are objectionable for using in food and pharmaceutical industry. The materials are not flexible and cannot be customised to suit requirements in different industries. Further the preparative procedures are complex and involve hazardous compounds and hence are not viable for preparing the barrier materials economically in an eco-friendly manner. An appropriate barrier material for the electronics, food and pharmaceutical industries, by a simple, eco-friendly and economical method which can overcome the drawbacks of the existing barrier materials and their preparations is the need of the day. The present invention is aimed at achieving the same for usage in the said industries.   Accordingly, the present invention provides a flexible layered film comprising graphene layer and a polymer layer which can act as a barrier material to suit food, pharmaceutical and electronics industry. The method of preparation is environmental friendly. STATEMENT OF INVENTION Accordingly the present invention provides a layered film, comprising a layer of Graphene and a layer of polymer; which acts as a shield for gas permeation; a layered film, comprising layered films of a layer of graphene and a layer of polymer, stacked on one another, such that Graphene layer and polymer layer are adjacent to each other, which acts as a shield for gas permeation; and a process for the preparation of a layered film, comprising a layer of Graphene and a layer of polymer, which acts as a shield for gas permeation, said process comprising acts of, (a) dissolving polymer in a solvent to obtain a solution of the polymer, (b) lodging the solution of the polymer on a layer of Graphene deposited on copper foil, in a mold, (c) evaporating the solvent from the solution of the polymer in the mold, (d) removing the layered film on copper foil from the mold and drying, (e) etching the copper foil from the layered film with Ferric chloride solution, and drying to obtain layered film comprising a layer of Graphene and a layer of polymer. BRIEF DESCRIPTION OF FIGURES The present invention will be readily understood by the following detailed description in conjunction with the accompanying figures, wherein like reference numerals designate like structural elements, and in which: Figure 1 shows a bilayered film comprising Graphene and polymer layer. Figure 2 shows Graphene deposited over Cu foil. Figure 3 shows Graphene deposited over polymer foil at various position. Figure 4 shows Raman mapping of graphene on the polymer at 1600 cm" Figure 5 shows SEM image of the cross-sectional morphology of PVB layer. Figure 6 shows the Schematic of the test and the moisture sensing device architecture. Figure 7 shows Ro/R plot for Glass glue interface (control experiment). Figure 8 shows R is the molar mass of calcium, 8 is the density and p is the resistivity of calcium. L and B are the length and width of the as deposited calcium. In the study, same values are used for both L and B. (Schematic of Ca- degradation test is given in figure 6). The resistivity of calcium is constant only above 100 run and hence calcium of thickness 150 nm is deposited to study the degradation from 150 to 100 nm. Ro is the resistance of the as deposited calcium initially. G. Results and discussions PVB 1, PVB 2, PVB 3 and PMMA 1, PMMA 2 are the neat sample polymer films of PVB and PMMA respectively. PVB/G(1), PVB/G(2), PVB/G(3) and PMMA/G(1), PMMA/G(2) are the PVB and PMMA coated grapheme films respectively. The permeabilities of neat PVB films as determined from calcium degradation tests are in the range: 0.05 - 0.3 gm m"2 day"1. Whereas for the PVB coated Graphene films, the WVTR value is of the order of 10"6 gm m"2 day"1. This shows the increased barrier of the neat PVB towards moisture due to the presence of graphene. Calcium thickness of 100 nm is the limiting factor to compare the barrier property below 100 nm. Similarly for the neat PMMA films, i.e., PMMA1 and PMMA2, the WVTR is about approximately 0.8 g m"2 day"1. The presence of graphene on the PMMA reduced the permeability further by about 5 orders in magnitude. This confirms the impermeability of graphene led to improved barrier property of the polymer irrespective of the polymer type. Table 1: WVTR at various time intervals calculated from the RJR plots Table 1 shows that permeability is reduced to a great extent in PVB/G and PMMA/G samples as compared to PVB/0 and PMMA/0. The significant reduction (<10 g/m /day) in the permeation establishes the usage of the layered film of the present invention. Thus the present invention provides a barrier material which is flexible, cost effective, and suitable to be tailor made for specific industrial application with the level of performance required in the field of packaging for food and pharmaceutical industries and barrier materials required for electronics industry.   WE CLAIM 1. A layered film, comprising a layer of Graphene and a layer of polymer; which acts as a shield for gas permeation. 2. The layered film as claimed in claim 1, wherein the thickness of the graphene layer varies from about 0.25nm to about 2.0nm; preferably about 0.3 5nm. 3. The layered film as claimed in claim 1, wherein the Graphene layer may comprise single or multiple layers of Graphene. 4. The layered film as claimed in claim 1, wherein the thickness of the polymer layer varies from about 30 um to about 300 urn; preferably about 100 um. 5. The layered film as claimed in claim 1, wherein the polymer is selected from a group comprising polyacrylics, polyurethanes, polyesters, vinyl polymers, vinylidene polymers, polyamides, polyimides, polyolefins and copolymers thereof. 6. The layered film as claimed in claim 5, wherein the polymer is polyvinyl butyral or polymethylmethacrylate. 7. A layered film, comprising layered films of claim 1 stacked on one another; such that Graphene layer and polymer layer are adjacent to each other, which acts as a shield for gas permeation. 8. A process for the preparation of a layered film, comprising a layer of Graphene and a layer of polymer, which acts as a shield for gas permeation, said process comprising acts of, a) dissolving polymer in a solvent to obtain a solution of the polymer; b) lodging the solution of the polymer on a layer of Graphene deposited on copper foil, in a mold; c) evaporating the solvent from the solution of the polymer in the mold; d) removing the layered film on copper foil from the mold and drying; e) etching the copper foil from the layered film with Ferric chloride solution; and f) drying to obtain layered film comprising a layer of Graphene and a layer of polymer. 9. The process for the preparation of layered film as claimed in claim 8, wherein the polymer is selected from a group comprising polyvinyl butyral, polymethylmethacrylate, polyacrylics, polyurethanes, polyesters, vinyl polymers, vinylidene polymers, polyamides, polyimides, polyolefins and copolymers thereof. 10. The process for preparation of layered film as claimed in claim 9, wherein the polymer is polyvinyl butyral or polymethylmethacrylate. 11. The process for preparation of layered film as claimed in claim 8, wherein the concentration of the solution of polymer ranges from about 2 % wt/wt to about 20 % wt/wt preferably about 5 % wt/wt. 12. The process for the preparation of layered film as claimed in claim 8, wherein the solution of polymer is a solution in a solvent selected from a group comprising methanol, ethanol, propanol, i-propanol, n-butanol, t-butanol, acetone, ketones, and toluene. 13. The process for the preparation of layered film as claimed in claim 8, wherein the deposition of Graphene on copper foil is obtained by a method selected from a group comprising chemical vapour deposition, by annealing of a polymer film and a sputtered carbon layer coated on top of copper foil; preferably by chemical vapour deposition. 14. The process for the preparation of layered film as claimed in claim 8, wherein the Ferric chloride solution, is a solution in water. 15. The process for the preparation of layered film as claimed in claim 14, wherein the Ferric chloride solution is of concentration ranging from about 30% to about 40%.