The US’s nuclear bombings of Hiroshima and Nagasaki, Japan, at the end of World War II, and the damage it wrought, have been etched on the collective memory of humankind.

But to really understand the horror of nuclear weapons and how important it is to push for global nuclear disarmament, the horror of such an attack must be brought home.

Imagine a normal day in Kuala Lumpur. People are just living their lives. Markets and shopping malls are bustling, restaurants packed with hungry customers, students studying hard and office workers making their way through rush hour traffic.

Then, a nuclear bomb goes off in the centre of the city. In less than a second, a plasma ball hotter than the sun grows to a size of 2 km across. Anything within this area vanishes instantly, without a trace, like water into vapour.

An intense light illuminates the city, capable of temporarily blinding anyone who looks at it. This light is extremely hot, and everything within a 13-km radius of the blast centre will burn.

An area of 500 sq km will become a raging inferno. So, one moment a person could be walking down the street and the next they are burnt alive, screaming in agony.

The blast is followed by a powerful shockwave that spreads throughout the capital. It is faster than sound, stronger than a typhoon and flattens anything in its path.

Anything built without steel reinforced concrete is levelled immediately and people will be sent flying like dust in the wind.

Condominiums, hotels, offices and shopping malls will collapse on the people inside them.

Petrol stations will explode, causing fires throughout the city as a dark mushroom cloud looms over the ruins. These fires will likely spread, possibly culminating in a firestorm that incinerates anyone who survived the initial destruction.

Distance will not bring safety. The shockwave can travel up to 21 km away. Someone in Puchong could be taking pictures of the mushroom cloud when the windows shatter and glass shards are sent flying, cutting anyone or anything in their path.

But the worst time will be the period after the immediate destruction is over.

When a natural disaster strikes people can count on the emergency services to come out to help save people and create order. But a nuclear explosion is like several natural disasters at once, magnified.

Hundreds of thousands or even millions of people need urgent and immediate medical attention and many will die before help arrives, if it arrives.

In toppled condominiums and office towers, thousands will be buried alive. Those lucky to be out in the street are stumbling about, deafened, blinded and in panic.

Escape to safety is difficult with roads blocked by debris. Hospitals can offer no refuge, they have been destroyed too, with medical personnel injured or killed.

Those in underground trains when the blast occurred may be spared, or people may survive through shear serendipity. But then it rains, radioactive ash and dust will be spread everywhere.

Radiation poisoning will affect any survivor who cannot protect themselves, possibly killing them in days. Those who manage to escape the worst are at risk of contracting cancer and dying years later.

Those who survive the attack will have to fend for themselves. There will be no help because the infrastructure would have collapsed. Ambulances will not be able to get through blocked roads, trains will not be able to travel on melted tracks, and aeroplanes will need clear runways.

The survivors will have to cope as best they can without proper access to food, water, electricity or communication systems. Even if help does arrive, the rescuers will be risking radioactive contamination.

Hospitals outside KL will do what they can to help but they will be overwhelmed by the massive influx of patients. No matter how well prepared the authorities can be for natural disasters, there will be little they can do to prepare for a nuclear attack.

World politics has been tense lately, and experts have repeatedly warned about the increasing risk of nuclear war as major powers rattle their sabres. Countries with nuclear weapons often claim that they are for their own safety, but all it would take is one terrible mistake to unleash hell on earth.

Malaysia is largely and wisely committed to international neutrality, and voted in favour of the 2017 Treaty on the Prohibition of Nuclear Weapons.

No Malaysian would want this horror to happen to them or anyone else. Hence, on the International Day for the Total Elimination of Nuclear Weapons, it is important that Malaysia remains committed to its stance against this existential threat.