Reliance, which operates the the world's biggest refining complex at Jamnagar in western India, is becoming more international in its focus. Previously, it has bought stakes in some overseas explorations and manufacturing assets.

"This is a significant step in globalising Reliance's operations, and we are proud to partner with ADNOC in this important project for the region," Mukesh Ambani, the chairman of Indian oil-to-telcom conglomerate, said in the statement.

Asia's richest man Ambani last week announced the appointment of Saudi Aramco chairman Yasir Al-Rumayyan as a director in Reliance's board and said this is the "beginning of the internationalisation of Reliance". The group hopes to formalise a deal to sell 20% stake to Aramco in its oil-to-chemical business.

In a joint statement, Relaince and ADNOC said they expected final investment decisions for the projects and awards of related engineering contracts to be taken in 2022.

A source familiar with the matter said the project could cost $2.1 billion.

The planned project at TA'ZIZ Industrial complex will have a capacity to produce 940,000 tonnes of chlor-alkali, 1.1 million tonnes of ethylene dichloride and 360,000 tonnes of PVC annually, the statement said.

Reliance and ADNOC had signed a memorandum of understanding in 2019 to build Ethylene Dichloride facility in Ruwais.

(Reporting by Nidhi Verma; editing by Barbara Lewis)

By Nidhi Verma and Rania El Gamal