The pace of technological advance in thepast few decades has opened new possibilities. Consider thetechnology for controlling emissions from cars, buses, andtrucks. Government regulations have driven this technologyas much as the technology has driven regulations, resultingin vehicle emission standards in industrial countries thathave become increasingly stringent-far more so than those indeveloping countries. These standards are deemed necessaryto adequately protect the public, especially from excessmortality and morbidity caused by air pollution. But airpollution is much more serious in many developing countrycities. Doesn't this argue for imposing standards justas stringent, since the technologies to achieve them are nowavailable? Moreover, since the private sector bears the costof adopting these technologies, there should be littledirect impact on the government budget, removing one of thepotential obstacles to implementation.