US Secretary of State Marco Rubio met Adani Group chairman Gautam Adani and Tata Sons chairman N Chandrasekaran in Mumbai on Wednesday morning before heading to Jamnagar in Gujarat to visit Reliance Industries' giant oil-refining complex, the world's largest single-site refinery, along with Vantara and giga factories being developed by the conglomerate.
Rubio, who arrived in Mumbai on Tuesday afternoon, first met Adani, followed by a meeting with Chandrasekaran, sources said.
Neither side released details of the meetings.
Adani heads one of India's largest conglomerates, with interests spanning ports, airports, energy, logistics and infrastructure. The group has also been expanding its renewable-energy and manufacturing businesses, sectors that are central to India's ambitions to strengthen domestic supply chains and attract global investment.
Chandrasekaran, who leads Tata Sons, the Tata Group's holding company, oversees a sprawling business empire with interests in automobiles, steel, information technology, aviation, electronics, and advanced manufacturing. The group has been investing in semiconductors and battery technology as India seeks a larger role in global technology and manufacturing supply chains.
Rubio's Jamnagar itinerary brings the focus to Reliance's industrial complex, which houses the world's largest single-site oil refinery, with a combined processing capacity of about 1.4 million barrels per day.
The site also hosts Vantara, a wildlife rescue, treatment, and rehabilitation initiative launched by Reliance Industries and Reliance Foundation under Anant Ambani's leadership. Spread across more than 3,500 acres, the centre focuses on the care and rehabilitation of injured, threatened and rescued animals, alongside wildlife conservation efforts.
Another major component of the Jamnagar complex is Reliance's planned new-energy manufacturing hub, the Dhirubhai Ambani Green Energy Giga Complex. Spread across more than 5,000 acres, the project is designed to house factories for solar photovoltaic modules, battery energy storage, green hydrogen electrolysers, fuel cells and power electronics.
The investments form part of Reliance Chairman Mukesh Ambani's strategy to build a large integrated clean-energy business alongside the group's established oil refining and petrochemicals operations. The facilities are intended to support India's energy transition and reduce dependence on imported clean-energy equipment.
Sources said Rubio will visit all three before flying back to the US.
The visit comes as India and the United States seek to deepen commercial and strategic ties, with energy security, manufacturing and technology among the areas of potential cooperation.
Rubio's Jamnagar visit puts energy and industrial investment at the centre of his India trip, with the Reliance complex emerging as a focal point for potential cooperation between Washington and New Delhi on global oil supplies.
The refinery's ability to process a wide range of crude grades makes it strategically significant as the United States explores expanding markets for Venezuelan oil and India seeks to diversify its energy supplies.
Rubio has said Washington is in discussions with Reliance about refining more Venezuelan crude as production in the South American country rises.