Adani Group and Abu Dhabi-based investment conglomerate International Holding Company (IHC) plan to jointly invest $11.5 billion over the next few years to build a mega aluminium plant that could catapult India's total capacity by nearly 50%, said people familiar with the matter. This would be the second metals venture for Adani after its copper smelter in Gujarat that began operations last year, reflecting the power and ports group's strategy to secure commodity supplies for its expanding infrastructure empire. Adani and IHC will collectively make the investment through debt and equity towards building an aluminium smelter in Odisha with an annual capacity of more than 2 million tonnes, said the people cited above. They didn't disclose the investment split between the two partners.