The extension was expected to facilitate participation of Ningbo Port of China in the project.
This follows the keenness shown by the Chinese port, the sixth largest in the world, in developing transloading operation at Sandheads, 232 kilometre south of Kolkata.
The Chinese team has visited Kolkata twice but could not visit Sandheads as it could not secure a no-objection certificate from the ministry of external affairs (MEA). Their last visit was earlier this month.
KoPT officials pointed out that they could not be taken to Sandheads without MEA clearance.