The traditional Vishu festival in the state of Kerala in South India is celebrated in April with extensive coordinated fireworks display. The influence of these celebrations on the immediate and long-term air quality and impact on the health and well being of the public needs research. The combustion clouds contain harmful fumes (sulfur dioxide, oxides of nitrogen) and particulate matter released at the surface. This study is focused on the influence of fireworks on the air quality at Kannur, India, during Vishu in April 2010 and 2011. Elevated concentrations of various air pollutants such as O 3, NO 2, NO and PM 10 were measured during the intense usage of fireworks. Surprisingly, the organic analysis of the Particulate Matter (PM) samples collected on Vishu day revealed the emission of a variety of hazardous organic compounds during the fireworks display. One of the unique observations in this work is the nighttime production of O 3 by the photodissociation of NO 2 from the flash of firecrackers. The concentration of O 3 was observed to increase two fold over the control days of observation during the same month. Moreover, the concentrations of NO 2, and PM 10 increased by 100%. The concentration of NO was reduced by four fold during the event. A scheme based on the organic combustion from fireworks and peroxyl radical mediation is proposed for the nighttime production of ozone. The diurnal profile of all pollutants except NO showed higher concentrations starting from the Vishu eve on April 14 to Vishu day on April 15 and this pattern repeated for years 2010 and 2011. The fireworks activities have been increasing every year and generation of pollutants at their increased levels for short duration can potentially cause adverse health impacts on a regional scale in a highly populated region. © 2011 Elsevier Ltd.