From sirens to silence: How Mumbai lost its daily wail

Hindustan Times

07-05-2025

For decades, at exactly 9.00am, a mechanical wail would ripple through Mumbai's neighbourhoods. It wasn't an emergency. It was routine. Mumbai, India – 06, May 2025: RPF team, with sniffer dogs conducting the mock drill rehearsal underway at the Chhatrapati Shivaji Maharaj Terminus (CSMT) by the Central Railway, in Mumbai, India, on Tuesday, May 06, 2025. (Photo by Bhushan Koyande/HT Photo)
The city's air raid sirens – mounted on rooftops of police stations, government offices, railway buildings and municipal infrastructure – were a holdover from a more anxious time. After the 1971 war, these daily tests became a civic ritual. Office-goers, schoolchildren, shopkeepers all knew the drill. The siren marked the start of the working day. People set their watches to it.
And then, one day, it stopped. No warning. No replacement. The sound simply vanished from the city's busy life, and little did anyone notice in the new era of digital watches and cell phones.
Today, as the country gears up for a nationwide emergency preparedness drill amid a notification from Ministry of Home Affairs, many Mumbaikars are being reminded of something they had long forgotten: those sirens weren't just background noise. They were part of a larger civil defence system.
Mumbai had over 270 such sirens, installed during the early '60s and '70s, covering key government, defence and civilian clusters across the city. The system was powered by MTNL copper cables, linked to a central control room. A single command could activate sirens city-wide -– a legacy trigger for the entire network. The 9am test wasn't just ceremonial. It helped check the integrity of the system itself: a daily confirmation that the grid was functional, ready for deployment.
It wasn't war that silenced Mumbai's sirens though – it was floodwater.
The devastating deluge of July 2005 crippled the underground cable networks that linked these sirens. While MTNL did later upgrade to optic fibre, the sirens relied on legacy signals and became incompatible with the larger advancement.
Since then, the sirens have been little more than rooftop relics. According to Directorate of Civil Defence, a part of Government of Maharashtra, only 126 sirens were technically in working condition as of March 2023. But they could not be remotely triggered. In case of an actual emergency, each one would have to be triggered manually with no city-wide coordination.
In August 2023, the DCD (GoM) executed a study with MTNL (Mahanagar Telephone Nigam Limited) to explore revival of the siren network. The idea was to replace analogue triggers with digital infrastructure, similar to Mumbai's City Surveillance project that relies on optic fibre, provides more bandwidth, and can be programmed to have varying wails to indicate the type of emergency.
The study included an audit of existing sirens, range limitations, network infrastructure implementation, and cost of reactivation. The plan was solid. But like many legacy upgrades, it got stuck in bureaucratic limbo, even lost relevance after two decades of silence. No further updates or information have been made public since.
But with 4G connectivity, smartphone alerts, and the National Disaster Management Authority's Common Alerting Protocol (CAP) – can't emergencies be handled remotely through smartphones?
Yes – but only to a point.
Sirens still offer something remote systems can't: instant, mass notification that doesn't depend on phones, apps, battery life, language, or even mobile signal. In case of a power outage or a network blackout, a siren still works as an isolated medium. That's why countries like Japan, South Korea, the U.S., and Israel continue to maintain and modernize their public siren networks.
They are deployed across varying disasters – earthquakes, tornadoes, hurricanes, military threats, and even curfews. For Mumbai, a heavy cloud burst is a natural, recurring use case.
Hence, sirens aren't outdated. They're redundancy by design.
Today's mock drill isn't just a box-ticking exercise. It's a timely nudge from the Centre to states: dust off the old systems, test what still works, fix what doesn't. Whether it's control rooms, SOPs, or rooftop sirens – preparedness is no longer optional.
For Mumbai, that means reassessing systems like its siren network – not as nostalgia, but as essential or critical infrastructure. The city already knows how vulnerable it is to floods, hurricanes, and large-scale disruptions. Relying entirely on smartphone alerts without a functional physical backup is a risk we can't afford.
As tensions rise globally, India isn't predicting war – but it is preparing anyway. And that means revisiting old civil defence systems, updating what can be salvaged, and acknowledging that worst-case planning isn't paranoia. It's civic duty.