After shutting its ports to the Chinese submarine and research vessel, Sri Lanka on February 3 welcomed Indian Navy submarine INS Karanj ahead of its Independence Day.

It marks a diplomatic win for India. But the threat of Chinese submarine docking in the Indian backyard is far from over as Beijing constructs a sprawling naval base in Bangladesh.

The Sri Lankan Navy made this announcement, adding that while the submarine is in the island country, it will participate in a submarine awareness program, and the submarine crew will be exploring tourist attractions in the country.

The submarine is a Kalvari-class diesel-electric submarine based on the French Scorpene class submarines. It is designed by the French naval group DCNS and manufactured by Mazagon Dock Limited in Mumbai.

“INS Karanj is a 67.5m long submarine with a crew of 53, and it is commanded by Commander Arunabh,” the Sri Lankan Navy’s aid in an announcement. The submarine will depart from the Sri Lankan port on February 5.

The Indian submarine’s port call to Sri Lanka comes in the backdrop of Sri Lanka, sitting on the tip of the Indian Ocean Region, putting a year-long moratorium on foreign research vessels from operating in its waters.

The moratorium that began on January 1 is seen as a big diplomatic and strategic victory for India that has raised alarm over the Chinese research vessels surveying the vast swathes of the IOR under the pretext of conducting scientific tests.

The data gathered through these tests is invaluable for the Chinese submarines seeking to navigate the shallow waters of Malacca Strait and through the East IOR, causing much consternation to India.

However, the political equation in the IoR is getting tricky, with Maldives’ new President, Mohamed Muizzu, upping the ante against India. The Maldives has given a green signal to the same Chinese research vessel to dock at Male, much to India’s chagrin.

Sri Lanka has been under China’s thumb since Beijing acquired the lease of Hambantota Port for 99 years. Sri Lanka gave Beijing a port right under India’s nose after the island nation failed to pay the Chinese firms.

The Indian concerns over Chinese ballistic missile trackers and research surveillance ships being allowed by Sri Lanka or Maldives are due to fear that Beijing could use them for spying in the name of marine exploration.

Besides the ostensible scientific goals, these surveys produce data on seabed conditions that serve both civilian and military purposes. While seismic data is critical in assessing geological conditions, the presence of hydrocarbons, water, and seabed conditions also affect the ability to detect submarines.

Research vessels involved in scientific research can also use their instruments for naval reconnaissance, gathering intelligence on foreign military facilities and vessels operating in the vicinity.

Besides, a Chinese submarine last docked in Colombo in October 2014, a move that was fiercely criticized by India. India viewed the docking as a violation of a 1987 agreement declaring that “ports in Sri Lanka will not be made available for military use by any country in a manner prejudicial to India’s interests.”

In 2017, Sri Lanka rejected a request from China to dock one of its submarines in Colombo as it was detrimental to regional peace and stability.

China’s New ‘Look South Policy’

Sri Lanka might have refused docking to Chinese submarines, but Beijing has found another toehold in India’s area of dominance. China has given two submarines to the Bangladesh Navy and is constructing a port in Cox’s Bazar, which was inaugurated in 2023.

Satellite imagery suggests that China has made significant progress on the naval base, and the size of the base indicates that PLA-Navy will soon gain “logistical access” to the base. In other words, the Chinese submarines will call and dock at the Bangladesh port for refurbishment and servicing. The experts are calling it China’s “submarine diplomacy”.

“Gaining a foothold in the Bay of Bengal would significantly level up the PLA’s ability to operate farther from China’s shores and create new challenges for India, as well as the United States and its allies,” a recent analysis of satellite imagery of the under-construction naval base in Bangladesh revealed.

Christened the BNS Sheikh Hasina Naval Base, after the incumbent Bangladesh’s Prime Minister Sheikh Hasina, the base is constructed on a sprawling 1.75 square kilometer. The construction began in 2020, and the base was inaugurated in March 2023 by PM Sheikh Hasina, who called it “ultra-modern.” Several Chinese officials, including at least two senior PLA-N officers, attended the ceremony.

“Satellite imagery from July 2023 shows that construction continues. Despite the ongoing work, Bangladesh has already stationed its Chinese-made submarines there. Once completed, the base will be capable of docking six submarines and eight warships simultaneously,” the report titled “Submarine Diplomacy – A Snapshot of China’s Influence along the Bay of Bengal” read.

The Bay of Bengal lies on top of the sea lanes of communication that connect China, Japan, and Korea with the Middle East and Africa, and through these lanes, half of the world trade passes.

Bangladesh officials have confirmed that the Chinese personnel are also involved in training its submariners on how to operate the submarines and the new base. Prime Minister Hasina has also noted that the facility could be used as “a service point for ships sailing in the Bay of Bengal” — a potential signal that the PLA-N may one day call at the port there.

China, on its part, has kept the details of the project under wraps as it would not like to antagonize India, which has repeatedly raised the increasing military presence of China and set up military infrastructure in its area of dominance.

For India, the presence of Chinese-built submarines in the Bay of Bengal makes it a very crowded water body as far as underwater activities are concerned. And it also legitimizes the Chinese presence in more ways than one.

The two Chinese submarines given to the Bangladesh Navy don’t pose a significant threat to India. But the two submarines did come with Chinese officials onboard to train and familiarize the Bangladesh crew with the vessels.

Also, the submarine base will need maintenance and operational support from Chinese personnel. Its proximity to India’s Eastern Naval Command, where its indigenous nuclear submarine is under construction, is a cause of concern.

China has long sought access to the Bay of Bengal and the Arabian Sea because of its limited and unfavorable maritime geography, particularly along the Western Pacific. The entry into the Bay of Bengal for China is being facilitated considerably earlier by Myanmar and now by Bangladesh.