Section 6(e) in The Petroleum and Natural Gas Regulatory Board (Guiding Principles for Declaring or Authorizing Natural Gas Pipeline as Common Carrier or Contract Carrier) Regulations, 2009
(e)When the extra capacity in a natural gas pipeline to be provided on a common carrier basis is less than thirty three per cent of the sum of the capacity requirements of the entity and the firmed up contracted capacity with other entities, the same will be made available - (i) on expiry of firm contracts, or (ii) by way of expansion of capacity in the natural gas pipeline:
