The first Pakistani Hangor-class submarine has reached its home port in Karachi. The submarine, named PNS Hangor, is the first of eight submarines of this class to be inducted into the Pakistani Navy by 2028, with four of these submarines to be built in Karachi.

The Hangor-class submarine is a derivative of the Chinese Type-39A attack submarine.The Hangor-class submarines being inducted into the Pakistani Navy are equipped with an Air Independent Propulsion (AIP) system. This system allows a conventional diesel-electric submarine to stay underwater for a longer duration, as it does not need to come to the surface or snorkel in order to charge its batteries. Coming to the surface to charge batteries makes a submarine more vulnerable to detection by UAVs, aircraft and surface vessels.The addition of these eight submarines, along with the current fleet of five submarines in Pakistani service, will push the total number of such vessels to thirteen. Of these, nine will be equipped with an AIP system.

The Indian Navy, on the other hand, currently has sixteen attack submarines and three strategic submarines in its fleet. The conventionally powered diesel-electric attack submarines are from three different classes: the Kalvari, Sindhughosh and Shishumar classes. Only six of these submarines from the Kalvari class will get a plug-in AIP system developed domestically by the DRDO.

India's submarine modernisation has struggled with delays and shortfalls. The Navy's 1998 plan to induct 24 conventional submarines by 2030 has not fructified. The Navy has added only six vessels, while four have been retired.

The long-pending P-75I tender for six to nine submarines, worth about Rs 70,000 crore, has advanced, with MDL and Germany's TKMS clearing technical evaluation. However, deliveries will take years.

This timeline means P-75I and Project-76 could progress in parallel. Project-76 submarines are expected to feature a modified DRDO-developed AIP system.The Navy is also looking to bolster its underwater arm by procuring indigenous nuclear-powered attack submarines under Project-77, while also leasing a nuclear attack submarine from Russia. However, all of these programmes are years away. The Indian Navy, though, continues to enjoy overwhelming numerical superiority over its Pakistani counterpart.