Edtech startup Doubtnut has raised ₹224 crore in a new financing round led by SIG and James Murdoch's Lupa Systems. Existing investors Sequoia Capital India, Omidyar Network India and WaterBridge Ventures also participated in the Series B funding round. Founded in 2016, the Gurugram-headquartered startup allows students to ask study questions by clicking a picture of the problem.