India, Sept. 26 -- The United States is investigating whether Waaree Energies Ltd., India's largest solar panel maker, is in violation of solar tariffs imposed on China and other Southeast Asian countries.

The US Customs and Border Protection has started a formal investigation into Waaree Energies and Waaree Solar Americas and imposed interim measures on "reasonable suspicion" on duty evasion, according to a public notice obtained by Bloomberg.

That, after the American Alliance for Solar Manufacturing Trade Committee alleged that Waaree Energies was mislabeling solar cells that originated in China as coming from India to avoid tariffs on Chinese solar products.

"Indian solar products have been among the lowest prices in the market, and...