Introduction: Ground level Ozone is one of the primary constituents of photo-chemical smog and breathing air laced with high ozone concentration has a marked effect on human health according to the World Health Organisation (WHO). According to the Ambient (outdoor) air quality and health factsheet of WHO "it can cause breathing problems, trigger asthma, reduce lung function and cause lung diseases". Several European studies have reported that the daily mortality rises by 0.3% and that for heart diseases by 0.4%, per 10 µg/m3 increase in ozone exposure.
This study analyses ozone concentrations monitored in Delhi, India, which is consistently recognized as home to the most polluted air among the megacities in the world by WHO. Delhi is known to have sever ozone pollution problem but it is perceived to be a summer phenomena. This study explores the seasonal variation in ozone concentration in Delhi's air and relative impact of other chemical and weather elements on it.