In order to promote resource conservation, ease solid waste disposal problems, and conserve energy, the Minnesota Legislature enacted a statute in 1977 banning the retail sale of milk in plastic nonreturnable, nonrefillable containers, but permitting such sale in other nonreturnable, nonrefillable containers, such as paperboard milk cartons. Respondents contended that the statute violated the Equal Protection and Commerce Clauses of the Constitution. The Supreme Court held that the ban on plastic nonreturnable milk containers stood in a rational relation to the State’s objectives, and had to be sustained under the Equal Protection Clause. It emphasized that the Minnesota Legislature could rationally decide that its ban on plastic milk jugs might foster greater use of environmentally desirable alternatives. Furthermore, the statute did not violate the Commerce Clause as constituting an unreasonable burden on interstate commerce. Even granting that the out-of-state plastics industry was burdened relatively more heavily than other Minnesota industry, this burden was not "clearly excessive" in light of the substantial state interest in promoting conservation of energy and other natural resources and easing solid waste disposal problems.