India has cancelled the extended NOTAM, notice to airmen, for a long-range missile test in the Bay of Bengal that was due to be held from December 17 to 20, according to the website of the Indian Defence Research Wing (IDRW).
However, IDRW’s website is the only one which has reported the cancellation so far.
The original NOTAM issued on December 12, had designated a massive 3,550-kilometer no-fly and no-sail zone over the Bay of Bengal between 12.30 on December 17, to 15.30 on December 20.
The IDRW says that this was the second such revocation in quick succession in December. Earlier NOTAMs for December 1 to 4 and December 6 to 8 were cancelled.
The cancellations have driven observers to question whether the NOTAMs were genuine preparations for a breakthrough in missile technology or were a calculated exercise to gauge the response times of Chinese “research” vessels frequently deployed in the Indian Ocean Region (IOR).
There is speculation that India is playing a cat and mouse game with the Chinese navy, the website said.
The original NOTAM, issued by the Directorate General of Civil Aviation on December 12, represented one of the largest safety corridors ever notified for an Indian missile test, stretching eastward from launch points near Chandipur in Odisha and Visakhapatnam’s Eastern Naval Command.
Such an expansive zone—far surpassing the 1,480 km buffer from a prior alert—hinted at the evaluation of an advanced long-range system, potentially the Agni-1 Intercontinental Ballistic Missile or the K-15 Submarine-Launched Ballistic Missile (SLBM), both capable of exceeding 1500 km and central to India’s nuclear deterrence triad.
The four-day window allowed flexibility for weather delays or technical adjustments, a standard precaution for Defence Research and Development Organisation (DRDO) trials conducted from integrated test ranges.
Yet, as with the two preceding alerts withdrawn earlier this month, this one too was scrubbed without explanation, echoing a pattern observed throughout 2025, IDRW points out.
In October and November, similar NOTAMs—ranging from 1,480 km to 3,545 km—were pulled back amid heightened maritime activity, prompting accusations of “foreign interference”.
Dual purpose
Defence analysts point to the recurring presence of Chinese dual-use survey ships, ostensibly for oceanographic research but equipped with sophisticated telemetry arrays to intercept missile flight data, trajectories, and re-entry signatures.
Speculation has mounted about the idea behind India’s repeated issuances and abrupt cancellations, whether they serve a dual purpose: not just missile validation, but also a low-cost intelligence operation to measure Beijing’s surveillance agility.
Reports indicate that as soon as NOTAMs are published, Chinese vessels like the “Xiang Yang Hong” series, “Lan Hai 101”, and “Shi Yan 6” reposition into optimal tracking positions, often within days, covering vast swathes of the Bay of Bengal and Andaman Sea.
By revoking alerts at the eleventh hour, New Delhi may be forcing these ships to burn fuel on false alarms, revealing deployment patterns, sensor ranges, and coordination with PLA Navy assets—insights invaluable for countering espionage in contested waters, IDRW says.
While the DRDO maintains silence on specifics, the episode underscores escalating Sino-Indian maritime tensions, where the Indian Ocean serves as a theatre for technological one-upmanship. With China’s expanding blue-water footprint—bolstered by bases in Gwadar and Djibouti—India’s strategic tests are not merely technical milestones but signals of resolve.
As the year 2025 closes, the unexecuted trial leaves room for a rescheduled launch, but the real yield may already be in the data on adversarial reflexes, fortifying New Delhi’s edge in an increasingly surveyed seascape, IDRW says.
Navy chief’s denial
Commenting on the previous postponements, India’s Chief of Naval Staff Admiral Dinesh K Tripathi, dismissed the idea that missile tests were postponed because of Chinese spy vessels as “a figment of imagination”.
He acknowledged that India monitors foreign vessels but stressed that such activity is normal maritime practice and not a trigger for test postponement.
Message to Chinese?
That said, Indian defence observers note that China’s surveillance presence is not accidental—Beijing has strategic interests in tracking missile tests and understanding radar, trajectory, and splashdown data, which could provide insight into India’s deterrent capability.
Among defence analysts and strategic observers, India’s recent pattern of issuing and then cancelling NOTAMs has sparked a wider debate– are these withdrawals merely operational adjustments, or do they represent a calculated message aimed at foreign intelligence watchers—particularly China?
India’s naval build up
Given the threat to it from China in the Bay of Bengal and the Indian Ocean at large, New Delhi is strengthening its naval presence here in terms of submarines as well as missiles. It is acquiring new vessels and longer ranger missiles and conducting tests, giving NOTAMs about firing or the launching of missiles over specified areas.
The K-4 submarine-launched SLBM is India’s advanced solid-fuelled system derived from the Agni series. The K-4 program develops a nuclear-capable Submarine-Launched Ballistic Missile (SLBM) to bolster the sea leg of its nuclear triad, addressing limitations of the shorter-range K-15 Sagarika.
Submarine Integration and Status
INS Arihant (commissioned 2016) and INS Arighat (2024) carry 4 K-4s each. S4/S4 boats (2025 onward) doubled to 8. By mid-2025, K-4 achieved full operational status on Arihant-class SSBNs.
The December 17-20, 2025, Bay of Bengal NOTAM (2520-3550 km zone) was expected to validate K-4 maturity.
The K-4 targets China/Pakistan from safe ocean depths, outranging K-15’s 750 km for triad completeness. It precedes K-5 (5,000+ km, in trials) and K-6 (8,000 km MIRV) for S5-class SSBNs by 2030s.
Third nuclear submarine
Naval Chief Admiral Tripathi said on December 2, that INS Aridhaman, India’s third indigenously built nuclear-powered submarine, is set to be commissioned soon and It in the final stages of its trial.
Speaking at the annual pre-Navy Day press conference, Admiral Tripathi confirmed that the advanced submarine has entered the final stages of its trials.
