Held : t 1) S. 28 of the Customs Act, 1962 speaks of three kinds of errors in regard to duties. One is non-levy, the second is short levy, and the third' is erroneous refund. Levy i~ linked to assessment. In the process of assessment two kinds of errors may occur. One is non levy and the other is short levy. The expres,ion "erroneously refunded" means refunded by means of an order which is erroneously made. [986 F-G] (2) S. 131 (5) of the Customs Ac~ does not speak of any limitatiOJl' iir regard to revision b}" the Central Government of its own motion t<J. annul or modify any order of erroneous, refund of duty. The provisions contained in Section 131(5) with regard to non .. Jevy or short levy cannot be equated with erroneous refund in as much as the three categories of errors in the levy are dealt with in s. 28. [987 D-E] (3) Notice u/s 28 of the Customs Act speaks of demand for money to pay back and the notice is required to be given within six months frorn the relevant date. In 1he case of erroneous refund, it would be six months from the date of actual refund. Jf nol refund has in fact been made limitation cannot be said to arise inasmuch as the' relevant date u/s 28: in the case of erroneous refund speaks of the date of refund. In the instant case the impugned order dated 20, April 1972 grnnted refund. Grant of refund is not actual refund. [986 G-H. 987 Al CIVIL APPELLATE JURISDICTION : Civil Appeal No. 1830 of 1975. Apveal by S~ecial Leave from the Judgment and Order dated 10-9-75 of the Delhi High Court in Civil Writ Petition No. 475/75. Soli Sornbjee, Ravinder Narain, Talat Ansari and Shri Narain, for the Appellants. V. P. Raman, Addi. Sol. Genl. for India, S. K. Mehta and Girish Chandrn, for the Respondent. The Judgment of the Court was delivered by RAY, C. J.-This appeal is by special leave from the judgment dated 10 September 1975 of the Delhi High Court.