Answer:
The purpose of the laws implemented by the Mexican government in the late 1990s was likely aimed at addressing environmental concerns and improving air quality. Switching to cleaner fuels, installing catalytic converters, and converting city buses to natural gas are measures commonly associated with reducing air pollution and promoting a more environmentally friendly approach to automobile manufacturing and operation. These actions reflect a commitment to environmental conservation and public health by minimizing the emission of harmful pollutants from vehicles.