This lecture explores the concept of social innovation, focusing on developing effective solutions to social and environmental issues. It delves into the origins, definitions, and types of social innovation, as well as the role of social entrepreneurship. Case studies like Aravind Eye Care and PlayPumps are analyzed to understand the challenges and successes of implementing social innovations. The lecture also discusses the differences between social innovation and social enterprise, emphasizing the importance of collaboration across sectors. Students learn about the key elements of successful social innovations, such as financial sustainability, productivity, and community engagement.