On the 20th April 2020, the end of the first strict lockdown in Morocco, 2403410 cases of the corona Virus were confirmed globally. The number of Morocco confirmed cases attended 2990 and 143 deaths were recorded. Due to the pandemic, all avoidable activities in the country were prohibited since the kingdom announced the general lockdown on 20th March 2020. This study aims at comparing the air quality status in Casablanca and Marrakech from Morocco, before the pandemic and during the confinement to show whether COVID-19 compelled lockdown may have saved lives by restraining air pollution than by preventing infection. We used the difference-in-difference and the Theil and Sen non-parametric approaches for univariate time series. We defined the before quarantine period as between the 16th February and the 19th March and the during quarantine as between the 20th March and 20th April. We assessed changes in air quality during vs. before the quarantine period in 2020 and compared these with corresponding changes in the same lunar calendar periods in 2016-2019. Then we calculated the avoided cause-specific mortality attributable to the decreases in NO2 and PM2.5 based on the concentration-response functions from previous studies. We found that NO2 dropped by -12 μg/m³ in Casablanca and -7 μg/m³ in Marrakech. PM2·5 dropped by -18 μg/m³ in Casablanca and -14 μg/m³ in Marrakech. CO dropped by -0.04 mg/m³ in Casablanca and -0.12 mg/m³ in Marrakech. This air pollution reduction had created human health benefits and had reduced mortality and saved lives mainly from cardiovascular diseases. Our results are in complete agreement with the worldwide studies. Yet, they should be interpreted carefully because of the potential common impacts NO2 and PM2·5 may have on health. Further investigation may be undertaken to explore the reduction in the concentrations of industry-related pollutants.