Delhi-Geographical Patterning of Ozone and Nitrogen Dioxide Gas (2019–2021) with Specific Reference to the Covid-19 Lockdown Periods

Delhi city is not only the country’s capital but is also always amongst the top most polluted cities of the world since many years. In this regard, pollution is discussed as a problem in a number of ways in which the pollutant also requires significant attention. Ozone is a naturally occurring gas in the atmosphere and is also formed due to human activities which are generally related to emissions of multiple kinds in an urban scenario. It is an impactful secondary pollutant capable of generating harmful impacts. Nitrogen Dioxide is an Ozone precursor which is an indicator of its strong impact on Ozone generation. The time period offered by COVID-19 national lockdown period pandemic provides an unprecedented window to study pollution concerns of multiple kinds in an urban area. The current study is an attempt to analyse the spatial trends in Nitrogen Dioxide and Ozone gas for the city in the peculiar absence of human activities. The time periods of COVID-19 are supplemented with data prior for a year to examine the fluctuations in trends when compared to the COVID-19 lockdown. Results clearly indicate a strong exhibition of geographical patterning for Nitrogen Dioxide and non-geographic distribution of Ozone in the city irrespective of the presence or absence of human activities. While Nitrogen Dioxide further indicated a decline geographically and temporally in the lockdown period, Ozone did not provide any pattern of trends. The findings are pertinent as they can not only help in identifying the geographic distribution of the pollutants in the city but also in checking if any possible explanations can be provided for such a phenomena.