Talks ended in New Delhi Friday on the $7.5 billion pipeline, which will have annual capacity of at least 21.1 billion cubic meters and is expected to come on stream in 2011.
According to the sources, the parties discussed Tehran's proposal to review the gas price once in three years to make it contingent on world prices. The proposal was quite a surprise for India as the previous agreement stipulated that the price remain unchanged for 25 years.
A government source said neither India nor Pakistan could abandon the project having provided huge investment in the pipe traversing Pakistan.
Iranian natural gas is highly important for India, whose rapidly developing economy needs steady supplies of fuels. Pakistan in its turn suffers electricity shortages.
The parties are optimistic about the talks, although they have only agreed on transit duty for gas pumped across Pakistan.
The pipeline project is opposed by the United States, which is striving to isolate Iran, but the sides have repeatedly stated their resolve to carry it through despite pressure from Washington.
