Online grocery Big Basket may have suffered a massive data breach following which details of more than 20 million users may have been leaked on the dark web, said a US-based cybersecurity firm. Data worth $40,000 ( ₹30 lakh) was sold, the Atlanta-headquartered Cyble Inc’s research team found during routine dark web monitoring, it was a statement in a blog post on Saturday. In June, delivery startup Dunzo had an incident in which a data break in which the personal information of more than 300,000 accounts was leaked.