VISHAL

A well-known threat to environmental health is air pollution. When a brown haze covers a metropolis, exhaust billows across a busy highway, or a plume rises from a smokestack, we are aware of what we are seeing. Although some air pollution cannot be seen, its pungent odor warns you. For the world's health and prosperity, it poses a severe threat. Over 6.5 million people die each year from air pollution-related causes worldwide, a statistic that has grown over the previous 20 years.