**1. Introduction**

Under the current circumstances, the entire world is at risk of widespread infection of COVID-19, a pandemic, affecting more than 208 countries [1]. According to recent research conducted by researcher [2], there were approximately 4,369,933 COVID-19 cases worldwide, of which 98% had mild infections, 2% have severe infections, and 15% of patients could not survived. On March 22, 2020, the Indian government decided to implement a complete lockdown to prevent the spread of COVID-19 infection.

COVID-19 showed a profound impact on human health as well as on the economies of most of the countries. According to the regulations of the World Health Organization (WHO), people over the age of 60 and children under 10 are severely affected by the coronavirus [3]. According to medical experts, this type of disease is somewhat similar to severe acute respiratory syndrome (SARS). In the earlier study [4] it was demonstrated the viral aerosol generation and airborne droplet transmission in case of SARS. As per some of the medical experts it was assumed the spread

of the infection mainly through droplets, and sometimes through hand contact or indirect contact, but still the exact transmission route of this virus could not been recognized.

In India, as of May 13, 2020, there are approximately 75,048 confirmed cases and 2,440 deaths [5]. In view of the seriousness of the infection various activities and operations related to social gatherings, travel, and industry, including all modes of transportation, advertising, construction, and restaurants were restricted, but groceries, milk, fruits and vegetables, medicines, etc., were allowed in limited manner. However, during this lockdown period, the reduction of various air pollutants were observed over numerous countries [1, 6]. It was also reported the deterioration of pollutants PM2.5, PM10, SO2, CO and NO2 during the period of China's lockdown [7]. Prior to lockdown, most Indian cities had pollutant levels with a high proportion of the Indian urban population [8, 9].

The impact of the COVID-19 pandemic has led to a rapid increase in the number of COVID-19 cases in DEL (about 14 million people) in India. The importance of particulate matter, temperature (°C) and relative humidity (%) in the spread of COVID-19 virus and its correlation with the total number of cases (TC), active cases (AC), recovery cases (RC) and death cases (DC) are particularly discussed for the duration from January 1, 2020 to May 15, 2020 over Delhi (DEL) and one of the neighboring cities (Gurgaon (GW)).

Additionally the study conducted by a group of researchers [10], is in close understanding of relationship between air quality and COVID-19 cases in China. Air contamination estimated as particulate matter (PM) had additionally been demonstrated to be impeding to human wellbeing [11–14] and lead to expanded death rates [15, 16]. The prior examination exhibited the observable impact of meteorological parameters particularly surface air temperature and relative dampness on particulate issue [17]. Different pollutants were incorporated to characterize Air quality through the record of CO, Ozone, SO2, NO2, NH3, Pb, PM2.5 and PM10 (NAAQS). Anyway, the most responsible toxins answerable for helpless air quality list in India are presently PM2.5 and PM10.

In the investigation over DEL [18], the PM has been considered as one of the risky contaminations liable for persistent bronchitis and Asthma. Thusly, thinking about the criticality of PM and current lockdown circumstance, the investigation of fine (PM1.0 and PM2.5) and coarse (PM10) PM information for seven different places of Delhi (DEL) and Gurugram called Gurgaon (GW), India was done. During the previous (January 1, 2020 to March 22, 2020) and lock-in period (March


*Consequence of Meteorological Parameters on the Transmission of Covid-19 DOI: http://dx.doi.org/10.5772/intechopen.98978*

23, 2020 to May 15, 2020), the daily analysis and comparison corresponding to the abbreviations mentioned (**Table 1**), was accompanied. Since the optimized T (°C) and RH (%) support droplet stability in the local environment, this may be beneficial to the widespread spread of the virus [19]. According to research conducted in different cities in Italy and China, the association between high frequency of corona cases/fatalities and persistently high levels of air pollutants for more than four years were also noticed (www.downtoearth.org.in).

In this chapter, we strive to understand the relationship between PM, T (°C) and RH (%) and their synergy on COVID-19 cases through DEL, corresponding to the total number of cases (TC), active cases (AC), by considering the data available between April 1, 2020 and May 15, 2020, recover cases (RC) and death cases (DC).
