The concentration of ground level ozone is reported to be increasing in most of the developing and developed nations. High ozone concentrations have been reported to be responsible for premature deaths, damages to flora and fauna, loss in crop yields and several other environmental impacts. Thus it is important find the causes which lead to ozone formation. But in most of the cases it is noticed that the research is directed towards only monitoring and reporting the trends of ground level ozone and its precursor pollutants. A considerable number of studies have reported that ozone formation is a regional phenomenon and needs to be addressed locally as well as globally. Considering the same; the present study aims to find out the factors responsible for the formation of ground level ozone in one of the megacities India (Mumbai). A new approach In the present study the time taken for formation of ozone after emission of precursors is taken in to consideration. This was accomplished by offsetting the ozone values by one hour and adjusting them with the precursor pollutants. The parameters selected for analysis were based on the available literature. Step-wise regression analysis of pollutants in logarithmic form was carried out in order to understand factors influencing ozone formation. In order to understand ozone formation in detail, the study was carried for individual seasons experienced in the unique tropical climate as well for the entire data set to corroborate the findings. The study concludes with highlighting most important factors which influence ground level ozone formation. The present study will help to understand the factors which are critical for formation of ground level ozone and how they change with respect to change in seasons. This is expected to help policy planers in their decision making.