The Tale of How a Menacing Virus Temporarily Improved the Natural Environment of the Long-Polluted Dhaka City

Abstract:

Recent studies document the evidence of improvement of the natural environment due to the COVID-19 induced slowdown of anthropogenic pollution in some parts of the world, including China, Italy, Spain, and the USA. Dhaka being one of the most densely populated and polluted cities of the world, the water bodies and atmosphere here face the brunt of pollution as being the obvious means to discharge the industrial effluents and gaseous emissions, respectively. It is, therefore, worth exploring the indirect association of the COVID-19 induced socioeconomic confinement with the improvement of the natural environment of Dhaka city. This study investigates the water quality parameters like turbidity, suspended particulate matter, and Chlorophyll at selected locations of the Dhaka peripheral river network using a remote sensing approach. LANDSAT Satellite images of Dhaka City for the lockdown period of the year 2020 and the same months of previous years have been processed using the ACOLITE algorithm and ArcGIS to obtain the temporal estimate of water quality parameters. The outputs from the remote sensing approach have been compared with the in-situ measurements for ground-truthing. A similar comparative analysis has been conducted on the land surface temperature using MODIS Terra products from NASA Earth Data and air quality parameters obtained from the AirNow website. Only after a few months of the lockdown ensued on 25th March 2020, there has been speculation addressing the improvement of quality in the cities' waterways and air. Study results show a significant association between the decay of economic activity and recovery in water and air quality. In general, the result demonstrates that for some of the river stretches, air, and land of Dhaka City, the change is significant, which is an indicator of environmental resiliency, showing how gracefully nature can heal itself if just left undisturbed.