SACHET emergency alert system: At around 11.40 am on Saturday, many smartphones across India suddenly played a sharp beeping sound, accompanied by vibrations. A pop-up message flashed on screens in English, Hindi and other languages with the headline ‘extremely severe alert’.

While many may have been taken aback by the sudden vibrations and sound, this was essentially a pan-India test of a mass broadcast system — called cell broadcast — to alert people during natural or manmade disasters.

Currently, the government already issues disaster alerts through SMS.…