LAKE, Justice.

The Plaintiffs’ Appeals

The plaintiffs contend that authority to issue exclusive franchises to pick up, collect, transport and dispose of trash and other refuse, as well as garbage, was conferred upon the Board by G.S. 153-272. The Superior Court concluded: (a) This statute authorizes the Board to grant an exclusive franchise for the collection and disposal of “garbage”; (b) this statute does not authorize the Board to grant an exclusive franchise for the collection and disposal of “trash”; (c) solid waste material in which “garbage” is inseparably commingled is “garbage”; *488 and (d) this statute does not authorize the Board to grant an exclusive franchise to maintain a landfill. The appeal of the plaintiffs relates to (b) and (d) of these conclusions.

For the reasons set forth in our opinion in Transportation Service v. County of Robeson, 283 N.C. 494, 196 S.E. 2d 770, we find no error in the adoption by the Superior Court, for the purposes of these cases, of the definitions of “garbage,” “refuse” and “solid waste” contained in G.S. 130-166.16, or in its conclusion that G.S. 153-272 does not authorize the Board of County Commissioners to grant an exclusive franchise for the collection and disposal of “trash,” so defined and not substantially and inseparably commingled with “garbage,” so defined.

The authority conferred by G.S. 153-272 upon the Board of County Commissioners to regulate the “disposal of garbage” would, of necessity, extend to the disposal of garbage by the operation of a landfill. However, since a landfill is also a method for disposal of wastes which are not “garbage,” within the above definition and so within the meaning of G.S. 153-272, there was no error in the conclusion of the Superior Court that this statute does not authorize the Board of County Commissioners to grant an exclusive franchise for the operation of a landfill.

We find, therefore, no merit in the plaintiffs’ assignments of error and, with reference to the plaintiffs’ appeals, the judgment of the Superior Court is affirmed.

The Defendants’ Appeals

The Superior Court found as a fact that the waste picked up by each defendant, pursuant to its regular schedule of service to its customers, includes “paper, bottles, cans, tree limbs, food scraps, rotten fruit, and food wrappers,” that each defendant estimates that the vegetable and animal food scraps and matter approximates 10% or less of the material collected and “such putrescible material is inseparable from the other solid waste” collected and disposed of by these defendants. To this finding there was no exception. It is followed in the judgment of the court by a paragraph designated “Finding of Fact No. 11,” to which the defendants did except. In it the court “found” that because of the inseparability of the entire mass of waste collected by each defendant into its putrescible and non-putrescible components, the entire collection constitutes “gar *489 bage,” within the meaning of G.S. 153-272. This paragraph is, in reality, a conclusion of law. It is supported by the above mentioned finding of fact to which no exception was taken.

Obviously, a scrap of bread, a chicken bone, a watermelon rind or a half-filled carton of soured milk thrown into a truckload of yard trash and discarded newspapers would not convert the entire mass into “garbage.” Where, however, there is a substantial commingling of “garbage” and “trash” into an inseparable mass, the whole becomes “garbage,” attractive to rats and dangerous to the public health. The drawing of the line between trivial and substantial commingling of the two types of material is a question for the exercise of sound judgment in each case, but we are not prepared to say that a “garbage” component amounting to 10% of the total mass is not sufficient to warrant the conclusion that the entire mixture is “garbage,” within the meaning of the statute. Thus, we find no error in the conclusion of the Superior Court that each defendant is presently engaged in the collection and disposal of “garbage,” and the defendants’ Assignment of Error No. 1 is overruled.

We also find no merit in the defendants’ Assignments of Error 2 and 3 relating to the conclusion of the Superior Court that the franchises granted by the county to the plaintiffs are severable, so that the invalidity of those portions of each purporting to grant an exclusive franchise for the collection and disposal of “trash” and for the operation of landfills does not, per se, compel the conclusion that the grant of the exclusive right to collect and dispose of “garbage” is also invalid.

We are thus brought to the defendants’ fourth assignment of error. This is directed to the Superior Court’s conclusion that G.S. 153-272 is a valid enactment of authority to county commissioners to regulate the collection and disposal of garbage and is not unconstitutional “on any ground alleged by the defendants.” The defendants’ assignment of error asserts that this conclusion is erroneous “because General Statute 153-272 is an illegal and unconstitutional delegation of power to the county commissioners by our legislators * * * . ” The only argument made in support of this assignment of error in the brief of the defendants is that G.S. 153-272 “does not lay down or point to any standards for the guidance of counties in the exercise of their discretion in granting exclusive franchises for the *490 removal and disposal of garbage within said county,” and for that reason is a violation of Article II, § 1, of the Constitution of North Carolina.

The general rule that legislative power, vested in the General Assembly by Article II, § 1, of the Constitution of North Carolina, may not be delegated is subject to an exception permitting the delegation to municipal corporations and to- counties of power to legislate concerning local problems. Jackson v. Board of Adjustment, 275 N.C. 155, 162, 166 S.E. 2d 78; Efird v. Comrs. of Forsyth, 219 N.C. 96, 12 S.E. 2d 889; Tyrrell County v. Holloway, 182 N.C. 64, 108 S.E. 337. There is no merit in this assignment of error.

One who seeks a judicial determination that a statute, or governmental action pursuant thereto, is unconstitutional must raise the question at the earliest possible stage of the proceeding, usually in his pleadings in the trial court, must point out the specific constitutional provision upon which he relies and must preserve the question for consideration by the appellate court through an assignment of error specifically directing attention to such constitutional provision and by argument in his brief directed thereto. Martin v. Housing Corporation, 277 N.C. 29, 41, 175 S.E. 2d 665; Rice v. Rigsby and Davis v. Rigsby, 259 N.C. 506, 131 S.E. 2d 469. As Justice Parker, later Chief Justice, said in the case last cited, “Constitutional questions are of great importance and should not be presented in uncertain form.” In United States v. Spector, 343 U.S. 169, 72 S.Ct. 591, 96 L.Ed. 863, the Supreme Court of the United States said, “But when a single, naked question of constitutionality is presented, we do not search for new and different constitutional questions.”

The franchise granted to each plaintiff provides: (1) The grantee will obtain and maintain its equipment and other facilities in conformity to the requirements of the State Board of Health and to applicable laws of the State; (2) it will render “reasonably acceptable service” to persons, firms and corporations in its area, the County Board of Commissioners reserving the right to determine any controversy arising as to “reasonable acceptable service”; (3) the grantee will furnish such service at a “reasonable price,” the County Commissioners reserving the right to determine any controversy which may arise as to such price, but in no event shall the price be less than the prevailing price for like services rendered in adjoining counties of this State; (4) the grantee will furnish its own landfill; and (5) *491 such landfill may be used by “the general public” upon payment of a “reasonable fee” for such use.

Each franchise provides that nothing therein shall be construed to prevent any person, firm or corporation from “personally disposing of its own * * * garbage * * * in a legal and lawful manner and in compliance with the laws, rules and regulations of the North Carolina Health Department.” The provision as to the use of the grantee’s landfill by the general public would seem to mean that the above mentioned right of any person, firm or corporation “personally” to dispose of his or its own garbage would include transporting it to such landfill.

It will be observed the franchise agreement: (1) Does not expressly forbid discrimination either in service or in price; (2) provides no minimum frequency of pick up of garbage; (3) provides no maximum price or standard for determining a “reasonable price”; (4) apparently leaves both service and price to individual negotiation, subject to complaint to the Board of Commissioners; (5) does not require the grantee to remove garbage from the premises of any person, firm or corporation with whom it has no contract or with whom any controversy arises pending the determination of such controversy by the Board of Commissioners; and (6) does not require the grantee to pick up garbage heretofore or hereafter thrown or deposited on or near the roadside or any other public place.

These and other circumstances appearing in the record seem to distinguish the present case from many of the decisions of other courts cited by text writers in support of general statements that the grant by a city of an exclusive contract for the removal of garbage constitutes a proper exercise of the police power. See McQuillin, The Law of Municipal Corporations, 3rd Ed., § 24.251; 56 Am. Jur. 2d, Municipal Corporations, § 462; Annot., 83 A.L.R. 2d 799. Numerous cases from other jurisdictions, cited by these writers, support the proposition that a city, in the exercise of the police power delegated to it by the State, may prohibit anyone other than the city itself, or an independent contractor with whom it contracts for the removal of garbage, to transport garbage over its streets. This is deemed a reasonable exercise of the police power for the protection of the public health. Many decisions cited by these writers hold, and we think it cannot be doubted, that the police power extends to reasonable regulations of the equipment used, the manner *492 of collecting and transporting, the method and place of disposition of garbage by a scavenger and the requirement that he obtain a license. This, obviously, is a different question from that presented by the grant of an exclusive franchise.

The most widely accepted, and we- think the most plausible, basis for the decisions sustaining the validity of ordinances prohibiting anyone other than the city itself, or its independent contractor, from transporting garbage is that the public health can best be protected if the city authorities have but one scavenger to supervise. See: City of Indianapolis v. Ryan, 212 Ind. 447, 7 N.E. 2d 974; O’Neal v. Harrison, 96 Kansas 339, 150 P. 551; Wheeler v. Boston, 233 Mass. 275, 123 N.E. 684; Board of Health of Grand Rapids v. Vink, 184 Mich. 688, 151 N.W. 672; Valley Spring Hog Ranch Co. v. Plagmann, 282 Mo. 1, 220 S.W. 1; Smiley v. MacDonald, 42 Neb. 5, 60 N.W. 355; Atlantic City v. Abbott, 73 N.J.L. 281, 62 A. 999; Spencer v. Medford, 129 Ore. 333, 276 P. 1114; Smith v. City of Spokane, 55 Wash. 219, 104 P. 249. It may be seriously questioned whether this reason applies to the grant of an exclusive franchise to collect and dispose of garbage for compensation, leaving, as does the franchise in the present case, every person, firm or corporation free “personally” to transport and dispose of his or its own garbage. G.S. 153-272 expressly authorizes the issuance of such a franchise.

The myriad cases cited by the above mentioned text writers disclose that in many areas, especially large cities, the right to collect garbage for use as hog feed or other commercial purposes is much sought after and not without substantial value. See: Jansen Farms v. City of Indianapolis, 202 Ind. 138, 171 N.E. 199; Wheeler v. Boston, supra; People v. Gardner, 136 Mich. 693, 100 N.W. 126, aff’d, 199 U.S. 325, 26 S.Ct. 106, 50 L.Ed. 212; Atlantic City v. Abbott, supra; State ex rel. Moock v. City of Cincinnati, 120 Ohio State 500, 166 S.E. 583; Cornelius v. Seattle, 123 Wash. 550, 213 P. 17. We are not concerned here with a business of minimal importance, either in value or in relation to the public health. Whether a person who contracts with a restaurant operator, householder, or industrial plant to purchase garbage produced on the premises of such vendor is to be deemed a person transporting and disposing of his or its “own” garbage, within the meaning of the franchise in the record before us, presents another interesting question, not now before us for decision.

*493 The police power is not unlimited. To survive a well aimed constitutional attack, the governmental activity must have not only a good purpose but also a reasonable relation to the promotion of the public health, safety, morals or welfare. See, in relation to the regulation of garbage collection and disposal: Wheeler v. Boston, supra; Valley Spring Hog Ranch Co. v. Plagmann, supra; In re VanDine, 23 Mass. 187; State v. Fisher, 2 Mo. 174; Coombs v. MacDonald, 43 Neb. 632, 62 N.W. 41; Atlantic City v. Abbott, supra. As we have noted, the franchises before us permit any corporation “personally” to transport and dispose of its own garbage. The only way that a corporation can “personally” do so is through its employees. The relation to the promotion or preservation of the public health of a distinction between transporting and disposing of corporate garbage by employees and by an independent contractor is not too clear for question.

On 6 December 1971, each of the defendants, pursuant to contracts with his or its customers, was engaged in a lawful business, which business was conducive to the maintenance of the public health, sanitation and welfare. Nothing in the record suggests that either of the defendants did not have the proper equipment or was not qualified to operate such business in a safe and lawful manner, that any customer was dissatisfied with his or its services or that the manner in which the business was operated endangered the public health, safety or welfare. On that date the Board of County Commissioners by official action, proeedurally correct, undertook to deprive each of these defendants of his or its right to continue so to serve his or its customers and to confer that right upon another by granting to such favored person an exclusive franchise to carry on such business. This is drastic governmental action which can be supported only by reasonable basis for the belief that there is a substantial public need therefor.

Counsel have not cited and our research has not disclosed any decision of this Court determining the validity of such governmental action. The nearest approach thereto in our reports appears to be State v. Hill, 126 N.C. 1139, 36 S.E. 326. That case, however, is not squarely in point. G.S. 153-272 purports to confer upon the Board of County Commissioners authority to grant licensed persons the exclusive right to collect and dispose of garbage for compensation. The reasonableness of the distinction made in these franchises between transpor *494 tation and disposition of garbage by the producer thereof “personally” in the transportation and disposition of identical garbage under identical circumstances by an independent contractor other than the grantee of the franchise is not before us in this appeal. It is not shown by this record to have been before the Superior Court. In affirming the judgment of the Superior Court, we do not determine this question. It may or may not be presented to the Superior Court in the further hearings provided for in its judgment on the question of the recovery of damages by the plaintiffs from these defendants.

Affirmed.