India has issued a Notice to Air Missions (NOTAM) warning airlines of potential GPS interference near Kolkata between November 13 and 17, 2025. This development—flagged by defence analyst Damien Symon—marks the third major air corridor affected in recent weeks, following similar anomalies around Delhi and Mumbai. The pattern has triggered serious concern within civil aviation and defence circles.
Three Metros, One Pattern: Strategic Red Flags
The interference across Delhi, Mumbai, and now Kolkata suggests a widening pattern rather than isolated incidents. These cities represent India’s densest aviation routes and hold political, economic, and military significance. Defence analysts warn that such disruptions resemble grey-zone tactics used globally, where adversaries quietly probe a nation’s response capability without triggering open conflict. The proximity of these disruptions to command centres, coastlines, and critical trade routes only amplifies the strategic implications.
DGCA Tightens Rules Amid Rising Spoofing Incidents
Responding to the risk, the Directorate General of Civil Aviation (DGCA) has mandated airlines, pilots, and ATC personnel to report GPS anomalies within 10 minutes of detection. The advisory requires real-time reporting of position deviations, loss of satellite integrity, or suspected spoofing. The move comes after a cluster of anomalies near New Delhi sparked debates about the reliability of GNSS data crucial to both civilian and military aviation.
What Is GPS Spoofing?
GPS spoofing involves broadcasting false satellite signals to mislead navigation systems. Unlike simple jamming, spoofing creates realistic yet incorrect location data. This technique has been increasingly observed in geopolitical hotspots, where state and non-state actors use it to hide movements, distort surveillance data, or test adversaries’ electronic defence preparedness.
How Spoofing Threatens Aviation Safety
GPS interference can cause navigation errors, route deviations, and autopilot disruptions—forcing pilots to switch to manual controls. During low visibility, spoofing can undermine satellite-based approaches, raising operational risks. Surveillance systems like ADS-B may transmit false coordinates, impacting both civil and defence situational awareness. Repeated interference attempts also pose escalation risks, hinting at electronic warfare probing.
The Road Ahead
As India confronts recurring GPS anomalies across three major metros, the issue has evolved from a technical nuisance into a strategic concern. With aviation safety and national defence at stake, improving GNSS resilience and electronic warfare preparedness is now an urgent priority for the country.
