U.S. Secretary of State Marco Rubio is set to visit the world's largest oil refinery in Jamnagar, India, owned by billionaire Mukesh Ambani's Reliance Industries, as diesel prices surge ahead of U.S. midterm polls.

The International Energy Agency has warned that constraints on the diesel market will likely keep prices elevated into the next year. To ease diesel prices, which affect American truckers, farmers, and shippers, U.S. President Donald Trump earlier this month paused sanctions on Russia to allow supplies from Moscow in the global market.

The Trump administration is using this trip to focus on business deals rather than policy and politics as Americans remain focused on the economy ahead of the midterm polls, experts told CNBC.

Not only is Ambani's flagship company Reliance investing in a U.S. refinery and is a key buyer of Venezuelan oil, but its strong ability to supply diesel has put Jamnagar on the map during Rubio's visit, they added.

On Tuesday, the U.S. Department of State announced that Rubio will be traveling to Samarkand in Uzbekistan and from there to Mumbai and Jamnagar in India, with no mention of a stop in New Delhi, between Oct. 17 and 22.

Rubio, who is on his second trip to India this year, will meet with some senior Indian officials and with business leaders "to promote opportunities for commercial investment and economic cooperation," according to the release.

US Ambassador to India Sergio Gor said Rubio will travel to Jamnagar to visit Reliance's refining complex and hinted that Ambani would meet the U.S. official, according to Bloomberg. Given Ambani runs Reliance, "I'd imagine he'd be there," Gor said, according to the report.

Later in an interview with Indian media outlet NDTV, Gor said that the visit to Jamnagar was scheduled given Reliance's "incredible" investment in the U.S. refinery project. Reliance did not respond to emails sent by CNBC seeking details on the visit. The State Department did not respond to CNBC's queries sent outside of working hours. The U.S. is facing exceptionally high diesel prices ahead of its November midterm elections, and the Trump administration has been looking for ways to increase fuel availability, Arpit Chaturvedi, South Asia Advisor at strategic advisory firm Teneo, told CNBC.

Jamnagar has "considerable export-oriented refining capacity," making a strong case for the U.S. to explore refined-product supplies, including diesel, he added.

Ambani, who SpaceX founder Elon Musk referred to as the real boss of India last week, has been developing ties with the Trump administration. In March, U.S. President Donald Trump thanked Reliance for its "tremendous investment" in the first new refinery project in the U.S. in the last 50 years.

Reliance, which is majority-owned by the Ambani family, has also emerged as the second-largest buyer of Venezuelan crude outside of the U.S., even as Indian state-owned firms remain largely unmoved by Trump's appeal to buy more of it.

Rubio will also use the visit to highlight "Reliance's plans for a large, new refinery in Texas, which is the site of heated midterm U.S. election races drawing national attention," said Atman Trivedi, a partner at Washington-based DGA Albright Stonebridge Group.

Reliance's is also "well-positioned to sell diesel," and other refined petroleum products to the U.S., he added.

The Jamnagar refinery is the world's "largest and most complex single-site refinery" with crude processing capacity of 1.4 million barrels per day, according to Reliance.