India and China's largest oil companies have agreed to jointly explore for oil and natural gas world-wide, in an attempt to put aside a long-standing rivalry and better use their combined financial resources and expertise to secure energy supplies for their fast-growing economies.

While the two energy-deficient countries already work together on several international oil projects, they also have a history of bad relations, and of proposing cost-reducing alliances to jointly buy foreign energy assets and crude oil that mostly have come to nothing.