Sirens will sound across India on Wednesday evening as part of a mock drill to prepare for emergencies. This comes at a time when tensions with Pakistan are high, following India’s recent air strikes on terror camps across the border.

The loud, wailing sound of an air raid siren is meant to warn people of danger, like a possible attack. It can be very scary and creates a sense of fear and urgency. These sirens have been used in many countries during wars or emergencies and are still important for public safety.

This report looks at the different kinds of sirens, their history, and how they affect people emotionally. It shows how this powerful sound has been used during times of conflict to alert and protect people.

The modern siren was invented over 200 years ago by French scientist Charles Cagniard de la Tour. Though it was first made to study sound, it later became a key tool in both military and civilian use.

Today, air raid sirens are used to warn people of incoming danger, like missiles or air strikes. These sirens usually last about three minutes, with a rising and falling wail that’s hard to ignore. Even when used during safety drills, their sharp, haunting sound can cause fear, stress, and anxiety. The sound is so loud and intense that it can shake people emotionally, reminding them of war and danger, even if it’s just a test.

Types of Siren

There are different types of sirens, each serving a specific purpose:

War sirens have two main sounds: the first is a chilling, oscillating wail that signals an imminent attack, often heard from several kilometers away, while the second is a steady, flat tone that lasts for about a minute, indicating that the danger has passed and it's safe to emerge. 

Civilian sirens, like those used by ambulances and fire brigades, emit a consistent tone without pitch variation, typically heard within a one-kilometer range, to clear pathways and signal urgency. 

Industrial sirens in factories are loud and continuous, used to signal shift changes, breaks, or emergencies. In case of a serious emergency, these sirens will continue until the situation is resolved.

Impact of air raid sirens

Air raid sirens, traditionally powered by large electric motors and often made of iron, are designed with horns or circular openings to project sound over great distances. These sirens can still be found atop old railway stations, military buildings, and government structures. 

The loud, wailing tone of a war siren can cause significant physical reactions, such as increased heart rate and sweating, particularly in those already vulnerable. In the 2023 Israel-Hamas conflict, there were reports of heart attacks triggered by the sudden onset of sirens. This phenomenon was also seen during World War II, demonstrating the severe emotional and physical impact these warnings can have on people.