Mumbai City (19.07° N, 72.87° E) is the true example of ‘diversity in extreme level’. This well-known city is commonly known as the financial capital of India and is the 12th richest city in the world. Mumbai city (Municipal Corporation of Greater Mumbai or MCGM) spreads around 437.5 km2, with 12.5 million population as per Census 2011, with a population density of 83,660 per km2 and approximately 6.5 million are living in the slums without proper access to water, sanitation and hygiene (WASH). There is a debatable topic, ‘water is a blessing or a curse?’ We know water means life but in monsoon season these views might lead to conflicts. Mumbai alone has recorded 585.5 mm precipitation in July resulting in severe flooding across the city. The slum communities of Mumbai are at the receiving end of these erratic patterns due to inefficient drainage and lack of basic facilities. This pandemic situation has proved again the urgency of WASH. WHO has already listed the COVID-19 virus as one of the most contagious diseases which has been spreading exponentially due to the poor toilet facilities, lack of access to clean water and unhygienic activities in slums. The survey data from different slum communities configures their perception related to WASH and our study links it with the pandemic and the resultant adaptive capacity ranking. Although most of the Mumbai slum has a good literacy rate (69%) but lack of awareness among these slum communities lead to a vulnerable situation. The slum clusters of Mumbai have become COVID-19 hotspots and also resulted in losses of jobs and human lives. Through FCM (Fuzzy Cognitive Mapping) and SWOT analysis, the study discovers present social, technical, and economic aspects and perception of these slum communities to analyze their adaptive capacity towards COVID-19. Keywords: WASH, COVID-19, Slum, Mumbai