JUDGMENT

SARKARIA, J.:- These appeals directed against a judgment of the High Court of Judicature at Gauhati raise a common question in regard to the interpretation and constitutional validity of sub-clause (a) of Cl. (26) of Section 10 of the Income-tax Act, 1961 (for short, called the 1961 Act). The appeals will be disposed of by a common judgment.

2. R. Takin Roy Rymbai (respondent in Civil Appeal 579 of 1975) belongs to Jaintia Scheduled Tribe and is a permanent resident of United Khasi-Jaintia Hills Autonomous District under the Sixth Schedule of the Constitution within the State of Meghalaya. He joined service under the Government of Assam in 1941. In the previous year relevant to the assessment year 1970-71, he was posed at Shillong as Secretary to the Government of Assam. The Assam Secretariat building and office, which constitute his place of work was within that quarter of the town which is included in Shillong Municipality and is not a part of the area described in Para 20 of the Sixth Schedule.

3. The Income-tax Officer took the view that the assessee s income from salary in the relevant year arose in the non-scheduled area and as such is not covered by the exemption provided under Section 10 (26) (a) of the Act.

4. the assessee claimed that his income from salary had accrued or arisen within the specified area and, as such, he was entitled to the exemption. In the alternative, he contended that this was not a valid condition for denying him the benefit of the exemption under Section 10 (26). The Income-tax Officer overruled these contentions and completed the assessment subjecting the assessee s salary to tax.

5. The assessee thereupon filed a petition under Article 226 of the Constitution in the High Court for impugning the assessment orders and the notices of demand for the assessment year 1970-1971, on the ground that sub-clause (a) of Section 10 (26) of the Act is invalid and ultra vires Article 14 of the Constitution.

6. The writ petition was heard by a Bench of three learned Judges of the High Court, which held that this exemption clause has been enacted for the benefit of the Scheduled Tribes residing in specified areas. The object of this exemption clause, according to the High Court, will be frustrated and made nugatory if the income of a member of the Scheduled Tribe residing in the specified areas, is made subject to tax merely because the source of such an income is outside that area. In its view, the classification between members of the Scheduled Tribes having income which accrues or arises to them from any source from the Tribal area of the specified territories on the one hand, and the members of Scheduled Tribe having income which accrues or arises to them from any source outside the Tribal area or specified territories on the 672 other, is not based on any intelligible differentia, the classification is artificial and is not based on any substantial distinction having a rational nexus to the purpose of the law. On the contrary, the condition contained in sub-clause (a) would defeat the very object of the exemption clause in Section 10 (26). For this enunciation the High Court has sought support from this Court s observations in S. K. Dutta, Income-tax Officer v. Lawrence Singh Ingty, (1968) 2 SCR 165.

7. On the above reasoning, the High Court has struck down the aforesaid sub-clause (a) as violative of Article 14 of the Constitution, allowed the writ petition and quashed the impugned notices and the orders of assessment.

8. The Department has now come in appeal before us after obtaining special leave under Article 136 of the Constitution.

9. The provisions of Section 10 of the 1961 Act are in the nature of exemptions. The various clauses of this section indicate the incomes which are to be excluded from computation of the total income of a person under this Act. For a proper perspective, it will be useful to have a look at the historical background of this provision.

10. The Indian Income-tax Act, 1922 did