Saudi Crown Prince Mohammed bin Salman has signed eight deals with India's Prime Minister Narendra Modi during a state visit to New Delhi, India’s Ministry of External Affairs said.
The agreements related to sectors including energy, defence, health, education, tourism and space.
Prince Mohammed arrived in India on Saturday to attend the two-day G20 summit in the capital.
The two sides have agreed to "focus on energy co-operation, particularly in the downstream sector" and recognised each other's economic capabilities, Ausaf Sayeed, a senior ministry official said.
Talks between Prince Mohammed and Mr Modi also covered subjects including renewable energy, energy efficiency, strategic petroleum reserves and the circular carbon economy.
Prince Mohammed said relations between India and the Arabian Peninsula covered "1,000 years of history".
India helped to “build Saudi Arabia over the past 70 years", he said.
The two sides agreed to set up a task force to help identify and channel investments worth $100 billion in the West Coast refinery project in India’s western state of Maharashtra.
New Delhi planned to set up the $50 billion mega refinery project with a capacity of 60 million tonnes a year, with co-operation between Saudi Aramco, Adnoc and companies in India.
The project was delayed due to the Covid-19 pandemic and concerns over the environmental effects of land acquisition for the initiative.
New Delhi said the two leaders agreed to establish a task force to ensure the project went ahead.
“The monitoring committee will ensure that the progress in this refinery project is done as per the plans laid out by both sides," Mr Sayeed said.
Prince Mohammed and Mr Modi also agreed that their countries would work together on semiconductors.
Dr Sayeed said the two sides also agreed to expedite negotiations over the India-GCC free trade agreement, which "would act as a catalyst" for strengthening economic co-operation between India and Saudi Arabia.
"They also agreed to strengthen co-operation in the FinTech field and explore trading in the local currencies," he said.
"The two sides have started discussions and proposals have been exchanged. We have worked out similar arrangements with other countries in the region."
India recently signed an agreement with the UAE to settle trade in Indian rupees, instead of US dollars.
The talks also covered the prospect of student exchange programmes, with Mr Modi suggesting a joint working group on education and skill development, as well as visa waivers for diplomats. India has a visa waiver for diplomats with other countries in the Gulf.
Earlier in the day, Prince Mohammed began his state visit, his first to India since 2019, with a ceremonial reception at the Presidential Palace.
He said the state visit would "ensure that our relationship is maintained and improved for the sake of both countries. And with the leadership of India’s Prime Minister Narendra Modi, I am sure this will happen".
India is Saudi Arabia’s second largest trading partner, while Saudi Arabia is India’s fourth largest trading partner.
Trade between both countries reached an all-time high of $52.75 billion between 2022 and 2023.