Interpretation means the process of application of mind; it is derived from the Latin term "interpretari". Interpretation is the process through which one also retains the true and correct intention of the law-making bodies as is laid in the form of the statute.
Ordinarily, the interpretation of the law is deemed to be solely the right of courts of law. As a result of that, they have developed some set of rules for helping them to do that, so that there are uniformity and lack of ambiguity in deriving the true meaning of the statutes.
Ø Rule of Ejusdem Generis
It is one of the essential principles of interpretation. The term itself suggests that it is 'of an equivalent kind', and helps when the statute isn't clear on the implications and coverage. Wherever there are general words following particular and specific words, the general words following particular and specific words should be confined to things of the same kind as those given, unless there's a clear manifestation of a contrary purpose. It is simply a rule of construction to help the Courts to search out the true intention of the law-makers.
The rule of ejusdem generis should be applied with great caution as a result of it implies a departure from the natural means of words, to convey them in a way that means or is the supposed intention of the legislature.
The Maharashtra University of Health and others v. Satchikitsa Prasarak Mandal & Others
While examining the doctrine, the Supreme Court held that the expression Ejusdem Generis which means "of the same kind or nature" is a principle of construction that means, once general words during a statutory text are flanked by restricted words, the meaning of the general words is taken to be restricted by implication with that means of restricted words.
Ø Rule of Harmonious Construction.
It is applicable wherever more than one provisions of a statute are applicable in a given scenario, any of the applicable provisions are not subject to another and all such provisions cannot be reconciled with one another, then all such provisions shall be interpreted to provide impact to any or all applicable provisions. This is referred to as the principle of harmonious construction.
If in an enactment, there are two provisions that cannot be reconciled with one another, they ought to be so interpreted that, if potential, the effect could also be given to each. In other words, a statute should be read entirely and one provision of the Act ought to be construed about other provisions within the same act to build a uniform enactment of the entire statute. Such a construction includes the benefit of avoiding any inconsistency or repugnancy either among a section or between a section and other components of the statute.
The meaning is so construed that both parts play a role in it. This rule of interpretation means that any section or part of a statute should be read concerning the entire act, i.e., the meaning should be construed in entirety, not singularly. If while constructing the meaning of a section, it conflicts with the meaning given in another, in all probability there is an error in interpretation. Hence if two sections in the same statute seem to give different meanings or lead to opposite directions, the interpretation should be such that it can accommodate both meanings.
In Raj Krishana v. Binod Kanungo, the SC observed that the Court must avoid a head-on-clash between two sections of the same statute. The Court should construe provisions that appear to conflict in such a manner that they harmonize.
In the case of KM Nanavati v. the State of Maharashtrait was held that by invoking the harmonious construction rule the SC held that the absolute power of the governor under Art.161 of the Constitution to grant a pardon or to suspend a sentence passed on a suspicious person is not accessible throughout the period till the matter becomes legal before the SC as otherwise, it'll conflict with the judicial power of that court provided underneath Art. 142 of the Constitution.
Ø Literal Rule of Interpretation
It is called the primary and most vital rule of interpretation; it states that the sole rule for the development of Acts of parliament is that they must be construed as per the intent of the Parliament that passes the act. If the words of the Statute are in themselves precise and unambiguous, then no more can be done, it is necessary to expound these words in their natural and standard sense. The words themselves declare the intention of the lawmakers.
The law ought to be read word to word and should not divert from the true meaning. To avoid such ambiguity, law-makers usually include a "definitions" section inside a statute that expressly defines the vital terms.
The main part of the section should not be construed in such a way as to render a condition to the section redundant.
Ø Rule of reasonable construction
This rule is also known in the maxim Ut res magis valeat quam pereat. According to this rule, while constructing the meaning of a statute, although we utilize the common or ordinary meaning of the words used in it. It should be done according to the following-
1. The objective intended to be fulfilled by it, for example, the wrongs it seeks to address.
2. The subject matter or the core concern of the act
If we ignore these two things and take the words at their literal, face value, chances are that the interpretation would be faulty. Only a well-rounded meaning would be of practical use, as it would help assign a sensible meaning to the act. Hence, the act of interpretation would begin from taking the literal or dictionary meanings of the words of a statute, subjecting them to scrutiny in light of its objective, and only if such meanings do not give a correct sense of the act, should we resort to altering the meanings of the words according to the context.
Ø Mischief Rule
This rule originated in Heydon's case in 1584. It is the rule of purposive construction because the purpose of this statute is most significant while applying this rule. It's called Heydon's rule because it had been given by Lord Poke in Heydon's case in 1584. It is known as the mischief rule as a result of the focus on hardening the mischief.
This rule was made to suppress the mischief and advance the remedy. In the Heydon's case, it had been held that four things need to be followed for a true and positive interpretation of all the statutes generally, that are as follows-
1. What was the common law before the creation of an act?
2. What was the mischief that this statute was enacted?
3. What remedy did the Parliament want or had resolved and appointed to cure the unwellness of the commonwealth?
4. An actual reason for the remedy.
SOME OF THE OTHER RULES OF CONSTRUCTION –
Ø Noscitur a Sociis: It is one of the rules of interpretation. According to it, the meaning of a word has to be derived from the words mentioned along with it in the statute. This is because words at times have contextual meanings, and support complete interpretation only when read with contiguous words. This rule can be used when the word carries the same meaning everywhere in the statute, but not where alternative meanings are possible. This rule, like other rules of interpretation, is not resorted to when using it would lead to absurdities of interpretation.
Ø Strict and Liberal Construction: They are both ways of interpretation of statutes. Strict construction means that the statute should be followed in the letter i.e. only that should be given effect which is expressly stated in the act. No external inputs or extended usage is allowed. Such a construction would give more importance to the literal meaning of the words, without putting much premium on external information. Liberal construction means that the statute has to be followed in the spirit of the act, i.e., whatever can be done to give effect to the intention of the legislature in making that statute has to be done. This will include sources other than the internal ones. For example, following the Mischief Rule, one can easily gain the intention of the statute, thus giving effect to its original objective.
Hence, the two modes only differ in the importance given to the exact and literal meaning assigned to words of statutes and the scope of interpretation. Moreover, strict construction is followed to the extent it is possible. When it does not seem feasible, then a liberal construction is utilized.
Ø Contemporanea Expositio Est Optima Et Fortissima in Lege: This expression implies that a contemporary meaning to an expression gives its best interpretation. With older statutes, the words involved in its exposition have gone through so many changes at times, that to derive the meaning as intended takes a lot of effort. In that situation, the meaning the words had when the law was made is taken. Hence, the statutes are to be interpreted as when they were made. It is only when there is a doubt regarding the meaning of the words, are the other meanings referred to, and that too, only as presumptive evidence as to the real meaning. Even though a statute has been misinterpreted wrongly for years, the courts have the authority to bring to it the correct interpretation. The only exception would be when, because of the wrong interpretation, the property has changed titles or day to day transactions have occurred.
 The Maharashtra University of Health and others v. Satchikitsa Prasarak Mandal & Others, (Civil Appeal no. 2050 of 2010)  Raj Krishana v Binod Kanungo, (1954) SC 202  K.M. Nanavati v. The State of Maharashtra, (1962) AIR 605