In 1967, Mazda developed an innovative rotary enginecompact, lightweight and smoothand mounted it in the Mazda Cosmo Sport.
During the 1970s, the Muskie Act was introduced in the United States. At that time, it contained the world's most stringent emissions regulations, forcing automobile manufacturers everywhere to rush to develop exhaust gas purification technologies. Although the enforcement of the act was later delayed, rotary engines, when fitted with antipollution systems, were able to successfully meet the levels described. As a result, Mazda managed to jump ahead of the competition with the domestic launch of the Luce AP (Anti-Pollution) in November 1972. As well as meeting the world's strictest emission standards before the Muskie Act was officially enforced, in 1973 it became the first car in Japan to be eligible for preferential tax treatment for low-pollution vehicles. Along with the Savanna AP, which was the second vehicle to attain this status, it was the cleanest vehicle in the world at that time in terms of emissions.
Subsequently, Mazda's antipollution technologies quickly spread to its reciprocal engines. The Grand Familia and Luce were both certified as low-pollution reciprocal engine vehicles in the same year.