[0001] The present disclosure described herein, in general, relates to a fuel injector for injecting fuel in an engine cylinder of an internal combustion engine. The present disclosure also relates to a method for operating the fuel injector. BACKGROUND [0002] The background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art. [0003] Internal combustion engines, specifically diesel engines often employ a so-called multiple fuel injection processes to transmit pressurized and atomized fuel through a one or multiple orifices of a fuel injection system into a combustion chamber or engine cylinder of an engine. However, such existing fuel injection systems particularly share the disadvantages of inadequate homogeneity of the air-fuel mixture cloud, cylinder wall and piston wall wetting/quenching, high combustion sound (knocking) and incomplete combustion and consequently, emission of higher quantities of effluents. [0004] The internal combustion engine operates in load and high conditions. Emission of particulate matter, i.e., soot particle is high in low load condition. As air density and pressure is very low in the combustion chambers at the low load application which offers little resistance to spray penetration of fuel from the fuel injectors. [0005] To overcome the generation of particulate matter, amount of air to be used in the combustion chamber is increased. With increase of air in the combustion chamber, production of nitrogen oxides (NOx) as emissions increase which is also strictly regulated. [0006] Further, production of soot particles and NOx can be controlled by homogeneous mixture of air-fuel which can be obtained by structure of fuel nozzle and timing of fuel nozzle spray. [0007] In view of the above, there is requirement for optimization of fuel nozzle structure for improving the emissions, combustion noise, and combustion efficiency and methods that reduce the above-mentioned drawbacks or disadvantages. OBJECTS OF THE DISCLOSURE [0008] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow. [0009] It is a general object of the present disclosure to provide a fuel injector for injecting fuel into an engine cylinder and a method for operating the fuel injector that prevents cylinder wall and piston wall wetting/quenching. [0010] It is another object of the present disclosure to provide a fuel injector and a method to operate the fuel injector that facilitates the formation of a homogeneous air-fuel mixture. [0011] Another object of the present subject matter is to provide a fuel injector and a method to operate the fuel injector that reduces knocking and harmful emissions of effluents. [0012] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings. SUMMARY [0013] This summary is provided to introduce concepts related to a fuel injector for injecting fuel into an engine cylinder and a method for operating the fuel injector. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [0014] The subject matter disclosed herein relates to a fuel injector for injecting fuel into an engine cylinder of a vehicle. The fuel injector comprising a nozzle body having a proximal end and distal end, the nozzle body define a tapered shape from the proximal end to the distal end which ends at the distal end; a first orifice located at bottom center of the distal end; a plurality of second orifices located on circumference of the nozzle body; a plurality of third orifices located in between the plurality of second orifices and the proximal end and on circumference of the nozzle body; wherein the plurality of second orifices located in between the first orifice and the plurality of third orifices; wherein diameter (Da) of the first orifice (103) is greater than diameter (Db) of the plurality of second orifices (104); and wherein diameter (Db) of the plurality of second orifices (104) is greater than diameter (Dc) of the plurality of third orifices (105). [0015] In an aspect, the first orifice has a spray angle (a), the plurality of second orifices has a spray angle ((3), and the plurality of third orifices has a spray angle (y), the spray angle (a) is greater the spray angle ((3) and the spray angle (y), the spray angle ((3) and the spray angle (y) are same. [0016] In an aspect, the spray angle ((3) is greater than the spray angle (y). [0017] In an aspect, injecting pressure (Pc) of the plurality of third orifices is greater than injecting pressure (Pb) the plurality of second orifices and injecting pressure (Pa) the first orifice, the injecting pressure (Pb) of the plurality of second orifices is greater than the injecting pressure (Pa) of the first orifice. [0018] In an aspect, the plurality of second orifices and the plurality of third orifices are offset to each other. [0019] In an aspect, number of orifice in the plurality of second orifices and the plurality of third orifices are same. [0020] In an aspect, the fuel injector is timed to perform fuel injection serially through the first orifice, the plurality of second orifices and the plurality of third orifices. [0021] In another embodiment, the present subject matter discloses a method for operating a fuel Injector at different feed stages for injecting a fuel into an engine cylinder. The method comprising spraying the fuel into the engine cylinder from a first orifice located around a central axis of nozzle body of the fuel injector when piston is moving from bottom dead center (BDC) to top dead center (TDC) of the engine cylinder; spraying the fuel into the engine cylinder from a plurality of second orifices which are evenly distributed around the nozzle body when the piston is about to reach TDC and spraying the fuel into the engine cylinder from a plurality of third orifices which are evenly distributed axially offset from the plurality of second orifices of the nozzle body when the piston reached almost TDC and also during descending from TDC. [0022] In an aspect, the fuel is sprayed in sequential order as the first orifice then the plurality of second orifices then the plurality of third orifices. [0023] In an aspect, the plurality of second orifices and the first orifice work to spray fuel in the engine cylinder based upon load conditions. [0024] In an aspect, the plurality of third orifices and the first orifice work to spray fuel in the engine cylinder based upon load conditions. [0025] In an aspect, sequential spray from the plurality of second orifices then the plurality of third orifices to spray fuel in the engine cylinder based upon load conditions. [0026] The above-disclosed aspects are advantageous in preparing a good homogenous air-fuel mixture and helping in complete combustion, thereby reducing the harmful emission of effluents. Further, the above-mentioned aspects prevent cylinder wall and piston wall wetting/quenching. [0027] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter. [0028] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components. BRIEF DESCRIPTION OF THE DRAWINGS [0029] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein: [0030] FIG. 1 illustrates structure of nozzle body of a fuel injector, in accordance with the present disclosure; and [0031] FIG. 2 illustrates a method for operating the nozzle of the fuel injector, in accordance with the present disclosure. [0032] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein. DETAILED DESCRIPTION [0033] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims. [0034] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof. [0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. [0036] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. [0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. [0038] In order to improve the homogeneity of an air-fuel mixture and reduce cylinder wall and piston wall wetting, knocking and incomplete combustion the present disclosure provides an improved fuel injector for injecting a fuel preferably in a liquid state into a combustion chamber of the internal combustion engine. [0039] In FIG. 1, 100 denotes the fuel injector which exhibits substantially a cylindrical body. The fuel injector 100 is to be mounted into an injector bore of the engine cylinder (not shown) and is capable to inject into the internal volume of the engine cylinder. The fuel injector 100 comprises a nozzle body 101 and a Hollow nozzle needle 102. The nozzle body 101 and the Hollow nozzle needle 102 are of tubular cylindrical shape with a variable cross-section. [0040] The nozzle body 101 having a proximal end 101a and a distal end 101b. The nozzle body 101 defines a tapered shape from the proximal end 101a to the distal end 101b. In another embodiment, the nozzle body 101 defines a conical portion having a plurality of orifices to dispense the fuel in to the engine cylinder. The nozzle body 101 comprises a first orifice 103, a plurality of second orifices 104, and a plurality of third orifices 105 at the conical portion and opening towards internal volume of the engine cylinder to dispense the fuel. The first orifice 103 is formed at the center of the conical portion at the distal end 101b while the plurality of second orifices 104 and the plurality of third orifices 105 occupy angular positions around the axis of the nozzle body 101 that are offset from the position occupied by the first orifice 103 and are evenly distributed. [0041] The plurality of third orifices 105 are formed on circumference of the nozzle body 101 and located in between the proximal end 101a and the plurality of second orifices 104. The plurality of second orifices 104 are formed on the circumference of the nozzle body 101 and located in between the first orifice 103 and the plurality of third orifices 105. The first orifice 103, the plurality of second orifices 104, and the plurality of third orifices 105 are axial offset to each other on circumference of the conical portion of the nozzle body 101. [0042] The number of the plurality of second orifices 104 and the plurality of third orifice 105 may be the same or different. In a preferred embodiment, the number of the plurality of second orifices 104 and the plurality of third orifices 105 is the same. In an embodiment, the diameter 'Da' of the first orifice 103 is greater than a diameter 'Db' of the plurality of the second orifice 104 and diameter 'Dc' of the plurality of third orifices 105. The diameter 'Db' of the plurality of the second orifices 104 is greater than the diameter 'Dc' of the plurality of the third orifices 105. The relationship between diameter of the first orifice 103, the plurality of second orifices 104, and the plurality of third orifices 105 is Da>Db>Dc. [0043] In an embodiment, the first orifice 103 has a spray angle a', the plurality of second orifices 104 has a spray angle '(3', and the plurality of third orifices 105 has a spray angle 'y, the spray angle 'a' is greater the spray angle '(3' and the spray angle 'y', the spray angle (3' and the spray angle 'y' are same. In another embodiment, the spray angle '(3' may be greater than the spray angle 'y'. The relationship between spray angle pressures of the first orifice 103, the plurality of second orifices 104, and the plurality of third orifices 105 is a< (3= y. It means that spray angle of the plurality of second orifices 104 and the plurality of third orifices 105 are same and wide. [0044] Injecting pressure 'Pa' of the first orifice 103 is less than injecting pressure 'Pb' and 'PC of the plurality of second orifices 104 and the plurality of third orifices 105 respectively. The Injecting pressure 'Pb' of the plurality of second orifices 104 is greater than injecting pressure 'Pa' of the first orifice 103 and less than injecting pressure 'Pc' of the plurality of third orifices 105. The relationship between injecting pressures of the first orifice 103, the plurality of second orifices 104, and the plurality of third orifices 105 is Pa