Riverine water quality engendered by policy interventions, episodic socio-cultural activities, and the COVID-19 pandemic lockdown: A case study of upper and middle Ganga, India

Abstract

Ganga is one of the most important rivers of India known for its unique anti-bacterial and self-purifying properties. While the river has been providing various direct and indirect services to the people in its densely populated basin, it has also been facing tremendous anthropogenic pressures in the past few decades due to developmental activities that deteriorated the riverine quality making it to the list of top ten world rivers at risk. The river also faces episodic challenges of pollution and health, due to frequent cultural and religious events involving mass bathing and rituals in Ganga waters by thousands of people. Considering the deteriorating quality of the river, various policy interventions such as Ganga Action Plan (GAP) in two phases, starting 1986, and the ‘Namami Gange’ programme under National Mission for Clean Ganga (NMCG) in 2014, have come into action to restore the river integrity. A historic deviation occurred during the Covid-19 pandemic lockdown in 2020-21, when all the anthropogenic activities came to a halt. The media and several studies reported rejuvenation of the river as a silver lining to the otherwise dark period. However, there were some studies that contradicted the same. To understand how and to what extent the river quality responded to the pressures and interventions, the present study critically analyses changes in some major water quality parameters (dissolved oxygen, biological oxygen demand, and coliform bacterial counts) in the upper and middle Ganga over the last four decades in response to various policy interventions, episodic mass bathing events, or minimal anthropogenic activities during the lockdown period, based on the available data and research studies by the authors. This is the first of its kind study comparing the river water quality changes through four decades assessing its changing suitability for ecological designated best use at different stretches bestowed by different management strategies and provides insight into the effectivity of various planning approaches for river restoration.