Now read this,,,,,,,,,,,,,, slowly.
Article58
Rights and duties of other States in the exclusive economic zone
1. In the exclusive economic zone, all States, whether coastal or land-locked, enjoy, subject to the relevant provisions of this Convention, the freedoms referred to in article 87 of navigation and overflight and of the laying of submarine cables and pipelines, and other internationally lawful uses of the sea related to these freedoms, such as those associated with the operation of ships, aircraft and submarine cables and pipelines, and compatible with the other provisions of this Convention.
PREAMBLE TO THE UNITED NATIONS CONVENTION ON THE LAW OF THE SEA
Pakistan can do squat to prevent this pipeline. Your territorial water ends at 12NM. You cannot prevent India or anyone else from laying down a pipeline even 13NM outside your coastline.