In December 2025, India has been engaged in a "cat-and-mouse" game regarding strategic missile testing in the Bay of Bengal, repeatedly issuing and then canceling or modifying NOTAMs (Notice to Airmen) due to the presence of Chinese surveillance vessels.
As of December 17, 2025, here is the current situation regarding the suspected long-range missile tests:
1. Repeated Cancellations and Rescheduling
Throughout early December 2025, India issued multiple NOTAMs that were subsequently withdrawn:
December 1–4: A NOTAM for a 3,500 km range (suspected K-4 SLBM or Agni variant) was issued but canceled on November 30.
December 6–8: A shorter-range NOTAM (approx. 1,480 km) was issued but also saw shifts in scheduling.
December 11: A new NOTAM was issued for a truncated range of 1,000 km, suggesting either a different missile or a "depressed trajectory" test to limit data collection by outsiders.
2. The Current Window: December 17–20
Most recently, India issued a fresh NOTAM for the period of December 17–20, 2025.
Range: This notice covers an extensive area of 3,550 km over the Bay of Bengal.
Suspected Missile: Defense analysts believe this indicates a full-range test of the K-4 Submarine-Launched Ballistic Missile (SLBM) or an advanced Agni series missile.
Safety Zone: The exclusion zone is one of the largest ever declared, suggesting complex maneuvers such as stage separation or MIRV (Multiple Independently Targetable Re-entry Vehicle) testing.
3. Why the Cancellations Occur
The primary reason for the "cancel-and-reschedule" strategy is the presence of Chinese "research" ships (often referred to as spy ships) in the Indian Ocean Region.
Vessels Spotted: Ships like the Shi Yan 6 and members of the Yuan Wang class have been active in the region.
The Risk: These vessels carry sophisticated electronic equipment capable of tracking missile trajectories and gathering telemetry data, which would allow China to study the performance and "signature" of India's strategic deterrents.
India’s Counter: By canceling NOTAMs at the last minute and issuing new ones for different dates or ranges, the DRDO (Defence Research and Development Organisation) aims to "blind" these surveillance efforts.
4. Strategic Significance
The persistent attempt to test a 3,500 km+ range missile signals that India is nearing the final operational validation of its sea-based nuclear triad. The K-4 missile, once fully deployed on Arihant-class submarines (like the recently commissioned INS Arighat), will allow India to target significant distances from the safety of the "bastion" in the Bay of Bengal.
In late 2025, there has been a significant surge in Chinese vessel activity in the Bay of Bengal and the wider Indian Ocean Region (IOR). While Beijing officially classifies these ships as "research vessels," Indian and international defense analysts generally refer to them as spy ships due to their sophisticated surveillance and missile-tracking capabilities.
As of December 2025, several specific ships have been flagged:
Recent Notable Vessels (Late 2025)
Shi Yan 6: In late November 2025, this geophysical research vessel was spotted south of the Andaman and Nicobar Islands. Its presence led India to postpone a planned missile test (originally set for Nov 25–27) to avoid revealing sensitive telemetry data.
Yuan Wang 5: A high-tech "space-tracking" ship was tracked entering the Indian Ocean in September 2025. This vessel is designed to monitor satellite launches and intercontinental ballistic missiles (ICBMs).
Shen Hai Yi Hao & Lan Hai 201: These survey ships have been active throughout November and December 2025, with Shen Hai Yi Hao specifically noted for operating deep-sea submersibles near the Maldives.
Strategic Concerns
The presence of these ships usually coincides with Indian missile tests or naval exercises (such as the Malabar exercise). The primary concerns for the Indian Navy include:
Data Collection: These ships use advanced sonar and sensors to map the seabed (bathymetry). This data is critical for submarine navigation and "silent" underwater travel.
Signal Intelligence (SIGINT): They can intercept electronic signals from Indian naval communications and radar systems.
Missile Telemetry: Tracking vessels like the Yuan Wang class can monitor the trajectory, speed, and accuracy of India's Agni or K-series missiles.
Stealth Tactics
In July 2025, a Chinese vessel was caught operating "covertly" roughly 120 nautical miles off India’s east coast. It had disabled its Automatic Identification System (AIS) to avoid public tracking, but it was eventually identified by French satellite intelligence through its radio frequency (RF) signature.
Note: Under international law, these vessels can operate in international waters (outside the 12-nautical-mile territorial limit). However, India maintains a "close watch" using P-8I surveillance aircraft and satellite monitoring.
