Several natural processes lead to the formation of ozone, a problematic secondary pollutant and greenhouse gas. Various factors influence the formation of ozone, including the presence of volatile hydrocarbons, carbon monoxide, and methane. Researchers also found that significant levels of ozone are emitted by fireworks. Findings are presented from a project investigating emissions of ozone from fireworks lit during Diwali festivities for Hindus in India and elsewhere during October and November. Evidence indicates that the fundamental process of ozone formation by fireworks ignition resemble ozone formation induced by ultraviolet radiation in the stratosphere. The study monitored concentrations of nitrogen oxides, ozone, and other microclimatic factors at a site in New Delhi.