The Tata Group is making a bet of over $5 billion, or about Rs 37,500 crore, over the next five years on Air India to turn around the national carrier, industry experts said. The amount, one of them estimated, covers the Rs 15,000 crore of debt that the group has taken over and losses it will have to fund. However, it doesn’t include asset-backed costs like plane refurbishment which will be higher, the person said.