New Emergency Messaging System (SACHET)
Context:
Millions of smartphone users across India recently experienced a sudden, loud beeping sound and vibration, accompanied by an "extremely severe alert" pop-up message in multiple languages.
This event was a large-scale pan-India test of the government's new mass broadcast system, called the SACHET emergency alert system, designed to warn citizens during natural or manmade disasters.
Global Context and Need:
The technology is endorsed by the International Telecommunication Union (ITU) and is utilized by over 30 countries, including Japan's J-Alert system (rolled out in 2007) and the US's Wireless Emergency Alerts (WEA).
With the increasing frequency of climate-related disasters like flash floods, cyclones, and extreme heatwaves in India, the UN's "Early Warnings for All" initiative recognizes cell broadcast as a critical, life-saving tool for climate adaptation.
How Does Technology Works?
SACHET uses Cell Broadcast (CB) technology, which allows authorities to simultaneously send short messages to millions of mobile phones within a defined geographic area.
Unlike SMS, which is a one-to-one channel, CB is a one-to-many technology.
It harnesses the routine, invisible communication between local cell towers and all the handsets within their reach to push emergency alerts out simultaneously.
CB does not require a phone number or an app to send a message.
It distributes content based on a subscriber's location via specific cell tower sites, making it highly privacy-preserving as devices are not individually tracked or registered.
Features and Advantages:
The alert overrides ongoing tasks (including calls) and bypasses network congestion.
It is delivered even if the phone is on silent or "Do-Not-Disturb" mode and uses distinct tones and vibration cadences to demand immediate attention.
The pop-up stays on screen until acknowledged.
The system can target specific small areas or the entire country and can deliver alerts in multiple languages, even reaching foreign visitors in the target zone.
The underlying mass broadcast technology for India's system was developed indigenously by the Centre for Development of Telematics (C-DOT) under the Department of Telecommunications.