In the wake of COVID-19, the vulnerabilities of the people residing in informal urban settlements have increased manifold. This study examines the pre-existing situation in Indian slum settlements, concerning WASH and housing, by analyzing the data from two rounds of NSS (76th-2019 & 69th- 2012). Data disaggregation across city size has also been looked at to deduce how million-plus city slum infrastructure differs from that of small city slums. The overarching objective is to infer slum dwellers' ability to withstand the impacts of COVID-19 or any other future public health emergencies.