In litigation , an interpretation of a statute including proviso matters the most . Since , a proviso can either result into fastening an additional liability or even can make one out of any liability by being an exception from the main enactment .
Whereas, different courts of law have analysed the proviso in such a way so that its enactment is given full effect .Further ,it is also treated in such a manner so that it does not become redundant .
Though there are various recent case laws on interpretation of a proviso in taxation and under various other enactments , but some of the evergreen classic ratio are as below:
a.PROVISO is to except something out of the enactment or to qualify something enacted therein which but for the PROVISO would be within the purview of the enactment- Kedarnath Jute Manufacturing Co. Ltd. v. Commercial Tax Officer, AIR 1966 SC 12
b. Proviso, as is well known, has four functions, as has been noticed by this Court in S. Sundaram Pillai v. V.R. Pattabiraman, [(1985) 1 SCC 591 in the following terms:
(1) qualifying or excepting certain provisions from the main enactment;
(2) it may entirely change the very concept of the intendment of the enactment by insisting on certain mandatory conditions to be fulfilled in order to make the enactment workable;
(3) it may be so embedded in the Act itself as to become an integral part of the enactment and thus acquire the tenor and colour of the substantive enactment itself; and
(4) it may be used merely to act as an optional addenda to the enactment with the sole object of explaining the real intendment of the statutory provision.”
Similar views were also taken in Swedish Match AB v. Securities & Exchange Board, India, (2004) 11 SCC 641.
c. Since the natural presumption is that but for the PROVISO, the enacting part of the section would have included the subject matter of the PROVISO , the enacting part has to be given such a construction which would make the exceptions carved out by the PROVISO necessary and a construction which would make the exceptions unnecessary and redundant should be avoided – Justice G.P. Singh`s “Principles of Statutory Interpretation” Seventh Edition 1999, p-163.
d.It is a cardinal rule of interpretation that a proviso to a particular provision of statute only embraces the-field which is covered by the main provision. It carves out an exception to the main provision to which it has been enacted as a proviso and to no other – M/s Ram Narain Sons Ltd. v. Asst. Commissioner of Sales Tax and others, 2 SCR 483.
e.A proviso must be considered with relation to the principle matter to which it stands as a proviso- Abdul Jabar Butt v. State of Jammu & Kashmir,  SCR 51.
f.that even though the proper function of a proviso is to except or qualify something enacted in the substantive clause which but for the proviso would be within that clause, there is no rule that the proviso must always be restricted to the ambit of the main enactment. It may at times amount to a substantive provision. This submission too does not advance the case of the respondent inasmuch as even if in a given case a proviso may amount to a substantive provision, making of such a substantive provision will have to be within the framework of Article 309 – Ishverlal Thakorelal Almaula v. Motibhai Nagjibhai,  1 SCR 367
g. In Ali M.K. v. State of Kerala –  11 SCC 632, 637, the Supreme Court made similar observations:
“The normal function of a proviso is to except something out of the enactment or to qualify something enacted therein which but for the proviso would be within the purview of the enactment. As was stated in Mullins v. Treasurer of Surrey (1880) 5 QBD 170; 42 LT 128 (referred to in Shah Bhojraj Kuverji Oil Mills and Ginning Factory v. Subhash Chandra Yograj Singh : AIR 1961 SC 1596 and Calcutta Tramways Co. Ltd. v. Corporation of Calcutta : AIR 1965 SC 1728), when one finds a proviso to a section the natural presumption is that, but for the proviso, the enacting part of the section would have included the subjectmatter of the proviso. The proper function of a proviso is to except and to deal with a case which would otherwise fall within the general language of the main enactment and its effect is confined to that case. It is a qualification of the preceding enactment which is expressed in terms too general to be quite accurate. As a general rule, a proviso is added to an enactment to qualify or create an exception to what is in the enactment and ordinarily, a proviso is not interpreted as stating a general rule’.”
by Anand Mishra, Founder Advocate, AMLEGALS
( The author is a leading advocate handling cases in Tribunals & High Courts of India. He can be contacted on email@example.com and for more pl referwww.amlegals.com )