The COVID-19 pandemic provided lessons for health policies across the globe. We assessed the knowledge, attitudes and practices of vulnerable populations in an informal settlement in Mumbai, India, during the pandemic. We discuss the viability and effectiveness of communication strategies using the results and provide suggestions for policy modifications regarding awareness generation and behavioral change during health emergencies. The study was conducted through a telephone survey among 460 respondents (233 men and 226 women) from April to May 2021. Television (94%) and family (70%) were the most common sources of information, but they were not the most trusted. Most respondents knew the causes and preventive measures of COVID-19, including vaccination. However, awareness did not always result in changes in attitudes and behavior- 66% perceived low or no risk to COVID-19, while 93% did not consider it essential to wear masks in workspaces and 78% did not sanitize hands before entering workspaces. More respondents had fears related to loss of employment (53%) than their physical (10%) or mental (4%) health. The study highlights the need for context-specific communication strategies among vulnerable populations. This includes reliable and accessible sources of information, an emphasis on information accuracy and detail, and a holistic and multidimensional approach to awareness and information sharing.