The petitioner in these three writ petitions is one and the same. It is a Company incorporated under the Companies Act, 1956. The petitioner manufactures cigarettes in its factory at Hosur, Dharmapuri District. The petitioner claims that it manufactures cigarettes for itself and for M/s. I.T.C. Limited. Cigarettes are subject to levy of excise duty under Tariff Item 4(11) (2) of the Central Excise Tariff, under manufactured tobacco. There was a partial exemption Notification 30/79 of Central Excise, dated 1-3-1979, hereinafter referred to as the Exemption Notification and the said notification, with its amendments by Notification Nos. 140/79-C.E. dated 30-3-1979 and 25/81-C.E., dated 1-3-1981, issued under sub-rule (1) of rule 8 of the Central Excise Rules, 1944, hereinafter referred to as the Rules, reads as follows :

"Partial Exemption to Cigarettes :

In exercise of the powers conferred by sub-ruled(1) of rule 8 of the Central Excise Rules, 1944, read with sub-Section (3) of Section 3 of the Additional Duties of Excise (Goods of Special Importance) Act, 1957 (58 of 1957) (hereinafter referred to as the Additional Duties of Excise Act) the Central Government hereby exemp