Tradesmen used some special mark or signage on their products
It was in the early times when the tradesmen used some special mark or signage on their products to differentiate their goods from the competitors. It made it easy for the consumers to identify particular goods to their origin and manufacturers. These special marks has evolved and established as a device to communicate with consumers for the traders today called as Trademark. A trademark can be any name, signature, word, letter, numeral, design, logo, letter, number and device. The advancement in technology and modernisation in image branding of goods and services has brought in new possibilities of having sound, taste, smell, colour, and shapes etc as trademarks.
Every country has two basic criteria for registration of a trademark; a sign must be capable of graphical representation and be capable of distinguishing the goods or services of one person from those of others. This requirement is applicable and problematic for registration of non-conventional trademarks. The European court of justice in Sieckmann v Deutsches Patent- und Markenamt  held that an unconventional mark although cannot visually be perceived can be registered if it can be represented graphically and is capable of distinguishing the goods and services from those of other marks.
The “Manual of trademarks practice" currently provides rules for registration of unconventional trademark for colours, three-dimensional marks, sound, moving images and hologram, but it is not restrictive as far as any sign or mark is graphically represented can be registered as a trademark.
A sign, which a business entity uses to differentiate and creates an identity for its goods or services, is a trademark. A trader should acquire ownership or a right to use over a mark such that the consumer can identify his goods or services, differentiate from the others, and create a link to its origin. For example, the trademark "Mc Donald’s," along with the golden arc distinguishes from its competitor KFC or Burger King, likewise the three-pointed star of Mercedes Benz distinguishes its car from BMW or any other manufacturer.
“A ‘trade mark' means any sign capable of being represented graphically which is capable of distinguishing goods or services of one undertaking from those of other undertakings."  The section necessitates three essentials for a trademark to be registered i.e., it should be a sign, it must be capable of being graphically represented and it must distinguish the good and services of others undertakings.
A sign can be referred as a thing or message about the good and services such that the qualification of a sign is not mere decoration.  Although a sign holds a very low threshold and considered very occasionally, ECJ has addressed its requirement to be essential such that the abuse of trademark law to gain unfair competitive advantage is prevented.  Any sign can protected as a trademark if it can be identified and distinguished from the goods or services of one business entity to those of other business entities  .
FUNCTIONS OF A TRADEMARK
"The essential function of the trade mark ... is to guarantee the identity of the origin of the marked product to the consumer or ultimate user by enabling him without any possibility of confusion to distinguish that product from products which have another origin"  .
The function of a trademark essentially remains the same as it was put in the Memorandum on the creation of an EEC trade mark  of a trademark with regard to law and business is principally the same ie., trade origin. The perception of using a trademark is to postulate a particular product/ service originates from a particular manufacturer or service provider. Through this basic function, a trademark derives all other functions such as the quality function and the advertising function economically. A trader creates a good relationship commercially if his trademark assures that the trade origin is the same and a consumer is assured of the quality of all the goods produced under that trademark; the advertising value of a trademark necessitates that there is a definite legal relationship between the trademarked goods and the owner of the trademark.
The ‘quality function’ of a trademark is the guarantee of a particular quality of the goods and services the consumer requires and which he is adapted. The “advertising function" is through which a consumer distinguishes and creates an association to one mark than that of others  .
Any sign or mark to be registered as a trademark must qualify three conditions set out under the Trade Marks Act, 1994:
it should be within the meaning of “Trademark" as defined under section 1(1)
it should not qualify under any or all six absolute grounds for refusal under section 3 of the Act and
it should not qualify under any or all three relative grounds for refusal under section 5 of the Act.
Absolute Grounds for Refusal
The term as referred ‘absolute’ under the TMA does not mean that a proposed mark is devoid of registration due to conflict of rights of other parties but signifies the deficiency of the proposed mark. Section 3 lays six absolute grounds for refusal: first is the basic ground such as the lack of distinctiveness. Second relates to the objections to marks consisting shapes. Third ground relates public policy or morality and deceptiveness. Fourth ground relates to the usage of marks prohibited by law. Fifth ground relates to the prohibited use of certain emblems or symbols and last ground relates to the applications made in bad faith.
Relative grounds for refusal
"Relative grounds" the term refers to conflict of rights over rights of another party. There was much discussion for many years on the question of whether the Registrar shall have any power at all to refuse registration of a mark for any reasons as such until the amendment to TMA 1994 in 2007  , which made it possible for the registrar as well as the opposition proceedings to raise objections.
REGISTRATION OF UNCONVENTIONAL TRADEMARKS
The preeminent way to sell a product or offer service is by marketing and advertising therefore, traders are always looking for innovative ways to make a consumer to commit to memory about their products. After having logos, numbers, names etc as trademarks it is not surprising that now traders are having colour, shapes, smell, sound etc as their trademark.
The basic registration requirement of a trademark under TMA is ‘graphical representation’ of the sign but the term is not defined under the Act. It laid down the requirement of Graphical Representation for a trademark to be registered subsequent to Art. 2 of the first Directive on trademarks ( 89/104/EEC) by The Council for European Communities – “A trade mark may consist of any sign capable of being represented graphically, particularly words, including personal names, designs, letters, numerals, the shape of goods or of their packaging, provided that such signs are capable of distinguishing the goods or services of one undertaking from those of other undertakings". 
Although the Act is ambiguous, its objective/ intention seem to be clear that no sign can be excluded from being registered if the sign fulfils the requirements under the Act. The role of the graphic representation requirement for protection of trademark have already received in number of cases.
Sieckmann V Deutsches Patent- Und Markenamt
The application filed before German patent and trademark office for the registration of an olfactory mark of the pure chemical substance methyl cinnamate. The applicant Sieckmann tried various methods for graphically representing the odour. He submitted the chemical formula (C6H5-CH = CHCOOCH3) and its description cinnamic acid methyl ester, provided with the sample of the odour in a jar, and a description of the scent as “balsamically fruity with a slight hint of cinnamon". The patent and trademark office rejected the application on the ground that the sign cannot be regarded as a trademark as defined by Council Directive 89/104/EEC.  On an appeal to Bundespatentgericht, it was held that although smell can distinguish one good from another but it was uncertain whether olfactory mark could be graphically represented and satisfies the definition under article 2 under the first directive, thus, submitted the following questions to the court:
Whether the expression “signs capable of represented graphically" includes only the signs which is visible or includes signs which cannot be perceived visually but can be represented graphically i.e. colours, smell etc.?
Does odour represented by a chemical formula, by depositing the smell in a jar, by a description or by a combination of all full the criteria of graphical representation under Art. 2?
The court was of the opinion that the intention of graphical representation was to enable a consumer to remember the origin, quality and reputation of an undertaking rather represent a product or service of one undertaking and distinguishing from the other. The purpose of a trademark is to device a consumer to enable him to distinguish the goods and services from one origin to the other and perceive visually, by smell, by sound. A registered mark gives an exclusive right and monopoly to the owner and the law imposes graphical representation, so that, by examining the register it must be possible to know the nature and scope of the sign, references and symbols of a registered trademark.
To fulfil the criteria of graphical representation it must meet two requirements
To retain honour right of exclusivity the mark must be complete, clear and precise
For the purposes of examination, the mark must be intelligible.
The ability to smell is one of the six-senses possessed by humans, it is one of the strongest ways to inflict ones reminiscence, consequently undertakings are adding pleasant whiffs to their products and striving to monopolise it as a trademark. The Ralf Sieckmann case has opened up a new dimension for registration of unconventional trademarks in essence - olfactory trademark. The case cleared the obstacles faced for fulfil the criteria of graphical representation. Ralf Sieckmann filed an application for registration of smell of “balsamically fruity with a slight hint of cinnamon". The European Court of Justice held that a sign can be graphically represented if it is clear, precise, self-contained, easily accessible, intelligible, durable and objective. With respect to smell it is a challenging task, the court has made it clear that a representation of a smell mark by the way of chemical formula is not adequate, clear and precise since it only reflects the ingredient of the product but not the smell.
It is not possible for every individual to analyse the chemical formula and infer the smell.
The depositing of the sample of the smell, even if accepted, it would be problematic to for publications as well by the passage of time due to precariousness of the odour changes and might evaporate entirely. By chromatographic analysis or referring to ingredient elements smells can be registered  , if the representation is with such accuracy and precision that there can be no possibility of confusion with any other smell.
One of the first cases for smell mark, No.5 fragrance by Chanel, was rejected on the ground that the smell of the perfume is the product/ good itself. The smell was described as “ “scent of aldehydic-floral fragrance product, with an aldehydic top note from aldehydes, bergamont, lemon and neroli; an elegant floral middle note, from jasmine, rose, lily of the valley, orris and ylang-ylang; and a sensual feminine note from sandal, cedar, vanilla, amber, civet and musk. The scent is also being known by the written brand name No 5.  " In UK two smell marks are registered
The trade mark is a floral fragrance/smell reminiscent of rose applied to tyres" (No.2001416) and
“The mark comprises the strong smell of bitter beer applied to flights for darts" (No.2000234).
John Lewis of Hungerford Ltd's filed trademark application for registration of “the smell, aroma or essence of cinnamon." The application was made to register the mark in Class 20 in respect of furniture and parts and fittings. The registration was refused on the ground that the description is cannot be accepted as the person who reads the description would know the smell of cinnamon already  . To determine the smell a supplementary representation is required. The officer referred to application to register Love Hearts sweets:
“I cannot accept that the description … is sufficient to enable a trader to determine precisely what the sign is … the description pre-supposes knowledge of the part of the trader of the Love Hearts product as sold over the years … this cannot be the correct approach. The description must stand on its own to identify the trade mark.  "
The above decision is contradicting to a certain extent with the allowance for registration of “The smell of fresh cut grass" for tennis balls  filed by John Lewis. In general, by reading the description any person would know the smell of fresh grass. But with this application the views of the hearing officer was different; the Board of appeal stated that it is registrable as “The smell of freshly cut grass is a distinct smell which everyone immediately recognises from experience. For many, the scent or fragrance of freshly cut grass reminds them of spring, or summer, manicured lawns or playing fields, or other such pleasant experiences."
Further, notably the decision of the Board was made with lack of deliberation as to the graphical representation was adequate and the question whether a verbal description fulfils the criteria of graphical representation has gone unanswered  .
The difference in views in the above cases creates a predicament on the registration of smell as trademark. There is no plausible way to make accurate description of a mark which fulfils the requirements laid down in Ralf Seickmann’s case.