Wastewater-based epidemiology has been recognized as a tool to monitor the progress of COVID-19 pandemic worldwide. The study presented herein aimed at quantitating the SARS-CoV-2 RNA in the wastewaters, predicting the number of infected individuals in the catchment areas, and correlating it with the clinically reported COVID-19 cases. Wastewater samples ( n = 162) from different treatment stages were collected from three wastewater treatment plants (WWTPs) from Mumbai city during the 2nd surge of COVID-19 (April 2021 to June 2021). SARS-CoV-2 causing COVID-19, was detected in 76.2% and 4.8% of raw and secondary treated ( n = 63 each) wastewater samples respectively while all tertiary treated samples ( n = 36) were negative. The quantity of SARS-CoV-2 RNA determined as gene copies/100 mL varied among all the three WWTPs under study. The gene copy numbers thus obtained were further used to estimate the number of infected individuals within the population served by these WWTPs using two published methods. A positive correlation ( p < 0.05) was observed between the estimated number of infected individuals and clinically confirmed COVID-19 cases reported during the sampling period in two WWTPs. Predicted infected individuals calculated in this study were 100 times higher than the reported COVID-19 cases in all the WWTPs assessed. The study findings demonstrated that the present wastewater treatment technologies at the three WWTPs studied were adequate to remove the virus. However, SARS-CoV-2 genome surveillance with emphasis on monitoring its variants should be implemented as a routine practice to prepare for any future surge in infections.

Water, Sanitation and Hygiene (WASH) practices are important factors in preventing diarrhoea. The objectives of this study were to assess the behaviour of the mothers of under-five children with regard to WASH practices, water quality, incidence rate of diarrhoea and the WASH predictors responsible for diarrhoea and water contamination, using multivariate regression analysis. The present study was conducted in households (n=55) having under-five children (n=88) based in an urban slum pocket of Mumbai city, India. Key satisfactory practices included (percent household following them in parenthesis) boiling of water (63.6%) and daily cleaning of storage containers (74.5%). Households followed unsatisfactory practices during water transfer (72.7%), handwashing (58.2%), defaecation location (96.4%) and disposal of children's faeces (98.2%). The incidence rate of diarrhoea among &lt;5-year-old children was 4.7 diarrhoeal episodes/100 child months. 86 and 39.7% of untreated and boiled drinking water samples had coliforms, while 12.5 and 5.1% had E. coli, respectively. Untreated drinking water and water sourced from shared taps were significantly associated with the incidence of diarrhoea (p&lt;0.05), and inconsistent in-house treatment of water was significantly associated with the presence of coliforms in drinking water (p&lt;0.05). The study results suggest that WASH advocacy and an improvement in sanitation-related infrastructure for the slum population can reduce diarrhoeal incidence.