The Georgia Board of Natural Resources (Board) issued a permit to Recycle & Recover, Inc. (RRI) for the construction and operation of a solid waste treatment facility. Shortly thereafter, RRI filed an application for a major modification of the facility. Before the Board took final action on RRI’s application, the General Assembly amended OCGA § 12-8-24 (e) (1) so as to provide that, with one ex*254ception not applicable here, a major modification “shall not be granted . . . sooner than three years from the date any such facility commenced operation. . . .” Based upon this amendment, the Board denied RRI’s application. On petition for judicial review, the superior court found that the Board’s decision was appropriate and did not violate RRI’s constitutional rights. In Case No. S95A1445, RRI appeals directly and, in Case No. S95A1447, RRI appeals pursuant to this Court’s grant of its application for discretionary appeal.
1. A superior court’s review of the decision of a state administrative agency can be appealed only by means of a granted discretionary application. OCGA § 5-6-35 (a) (1); Rebich v. Miles, 264 Ga. 467 (448 SE2d 192) (1994). Therefore, we dismiss RRI’s direct appeal and address the merits of the appeal brought pursuant to the grant of RRI’s discretionary application. Cobb County v. McColister, 261 Ga. 876 (413 SE2d 441) (1992).
2. RRI contends that the Board’s decision giving retroactive effect to the amendment of OCGA § 12-8-24 (e) (1) constitutes an unconstitutional application thereof.
In the exercise of the police power, the General Assembly is authorized to place “[restrictions upon land use in order to protect and preserve the natural resources, environment, and vital areas of this state.” Ga. Const, of 1983, Art. III, Sec. VI, Par. II (a) (1); Hayes v. Howell, 251 Ga. 580, 585 (2) (b) (308 SE2d 170) (1983). It was in the exercise of this police power that the General Assembly amended OCGA § 12-8-24 (e) (1). An enactment under the police power does not ordinarily violate any constitutional prohibition against retroactive statutes. Nevertheless, our Constitution forbids passage of retroactive laws which injuriously affect the vested rights of citizens. Fortson v. Weeks, 232 Ga. 472, 483-484 (7) (208 SE2d 68) (1974); Bullard v. Holman, 184 Ga. 788, 792 (193 SE 586) (1937). Thus, if RRI has a vested right which would be injuriously affected by application of the amendment of OCGA § 12-8-24 (e) (1), then our Constitution requires that that amendment be applied prospectively rather than retroactively.
The term “vested rights” means “ ‘interests which it is proper for (the) state to recognize and protect and of which (the) individual cannot be deprived arbitrarily without injustice.’ [Cits.]” Hayes v. Howell, supra at 584 (2) (b). A statute which confers a right upon an applicant seeking to alter the use of his property confers no vested rights upon all property owners. See Stone Mountain Indus. v. Wilhite, 221 Ga. 269 (144 SE2d 357) (1965). However, a property owner “can avail himself of the privilege thereof while it remains in the [statute].” Stone Mountain Indus, v. Wilhite, supra at 269. Thus, if a property owner becomes an actual applicant seeking to alter the use of his land, he has a vested right to consideration of his application *255under the statutory law then in existence. Banks County v. Chambers of Ga., 264 Ga. 421 (444 SE2d 783) (1994). See also Inner Visions, Ltd. v. City of Smyrna, 260 Ga. 902 (400 SE2d 915) (1991). Compare Jackson v. Three Aces Co., 249 Ga. 395 (291 SE2d 522) (1982) (involving state authority under the Twenty-First Amendment).
Banks County is not distinguishable on the basis that it involved the question of an applicant’s compliance with the local zoning ordinance. See OCGA § 12-8-24 (g). Just as requiring permits for solid waste disposal is an exercise of police power, so too is the regulation of zoning. Michiels v. Fulton County, 261 Ga. 395, 397 (2) (405 SE2d 40) (1991); Corey Outdoor Advertising v. Bd. of Zoning Adjustment, 254 Ga. 221, 224 (3) (327 SE2d 178) (1985). In either instance, our Constitution prohibits a legislative exercise of the police power so as to injure the vested rights of citizens. Thus, Banks County correctly held that the filing of a then-proper application for a sanitary landfill permit gives the landowner a vested right to issuance of the permit. Banks County, supra at 423 (1) (citing Southern States Landfill v. Walton County, 259 Ga. 673, 674 (1) (386 SE2d 358) (1989)).
In the instant case, RRI applied for modification of its permit less than three years after commencing operation of its facility, but before the amendment to OCGA § 12-8-24 (e) (1) imposed the three-year waiting period. Giving retroactive effect to the amendment would result in a delay of the decision on RRI’s application for three years after operations commenced. “ ‘Justice delayed is often justice denied.’ ” Davis v. Davis, 222 Ga. 579, 581 (151 SE2d 123) (1966). Delaying a remedy for three years is not merely procedural and should not, therefore, be applied retroactively. Compare Bullard v. Holman, supra at 791 (2). “[F]or practical purposes the existence of a right depends on the availability of an effective remedy to enforce it.” (Emphasis supplied.) 2 Sutherland Stat. Const., p. 399, § 41.09 (5th ed. 1993). It follows that the trial court erred in upholding the Board’s decision giving the subsequent amendment to OCGA § 12-8-24 (e) (1) retroactive effect over RRI’s pre-existing application for modification. However, we do not reach the ultimate question of whether RRI is entitled to issuance of a permit for major modification.
Appeal dismissed in Case No. S95A1445. Judgment reversed in Case No. S95A1447.
All the Justices concur, except Hunstein, J., who concurs specially; Benham, C. J., Fletcher, P. J., and Sears, J., who dissent.