The present dilemma concerning the build-up in air pollutants from internal combustion engine emissions has stimulated interest and concern at all levels of society. Efforts so far have been directed towards exhaust clean-up and reduction in injested lead compounds which offer only a temporary solution to the overall problem. Additionally, most authorities fail to mention that carbon dioxide is also an undesirable air pollutant.The use of an overall energy systems concept has resulted in a concentrated University research effort which may lead to a solution of this environmental problem in its broadest definition. The objective of the research has been the development of a hydrogen-fueled internal combustion engine. Results to date indicate that this type engine is not only technically possible but also economically feasible. It remains, however, for industry to apply its expertise in technical and management capabilities to assure further improvement with respect to cost, reliability, maintainability, safety, and related factors.This paper firstly places in perspective the overall air-pollution-by-vehicles problem, secondly proposes its long-range solution, thirdly outlines previous efforts which led to the development of the first “emission-free” internal combustion engine, and finally presents the challenge for industry to improve on the suggested approach or develop a better solution to this environmental problem.