Night after night in Yemen’s beleaguered capital, Sana’a, I hear the continuous clack-clack-clack of anti-aircraft fire and the low hum of fighter jets overhead. I’m writing this sat in the corner of my bathroom, the “safe” space farthest from the window. It’s almost midnight and the electricity has cut again, leaving the glow of my laptop screen as the only light.

My thoughts turn to my colleagues and friends, who are almost certainly awake as well with their families. This perpetual state of fear is nothing new. It’s been going on since the conflict started over five months ago and people are terrified that things could be about to get even worse.

More than 1,000 children have been killed or injured – a number that rises every day

This war has left Yemen, already the poorest country in the region, mired in a humanitarian crisis. Coalition forces led by Saudi Arabia have been conducting a bombing campaign to try to force out rebels from the Houthi sect, who overran the country in March, and restore the previous government. Conflict has since spread to 20 of Yemen’s 22 provinces. Ordinary people have paid the price for the violence – 21 million people are in urgent need of humanitarian assistance now, more than anywhere in the world, including Syria. The UN estimates that some 2,000 people have been killed so far, nearly a quarter of them children.

The crisis has been compounded by the fact that getting aid into Yemen and transporting it around the country is very limited. Aid agencies like Save the Children are frantically trying to scale up our response, but it’s almost impossible when we can’t get relief supplies into the country. The recent bombing of Hodeida port – the key entry point for supplies to the hungry people in the north and centre of the country – was the last straw, putting the aid effort in jeopardy at a time when people are running out of food, water and medicine.

Now rumours are rife that an escalation of attacks on the capital by Saudi-led coalition forces is imminent, in an attempt to drive out the Houthi opposition. If that happens, aid agencies could be forced to pull out altogether or to order their staff to stay indoors. The impact on one of the world’s most vulnerable populations would be devastating.

People are already desperate – I met a mother yesterday who had sold her family’s last mattress to buy her three-year-old son medicine. Now she and her children sleep on the cold, hard ground. She has nothing left to sell.

Everywhere I go people talk about food, or rather the lack of it. The spectre of famine is stalking large areas of the country. Yemen is slowly being strangled by a de facto blockade that prevents enough food and medicine getting to the families who need them most. If we don’t act soon, thousands of children will die from hunger-related causes before the year is out.

Across the country civilian infrastructure, including health facilities, markets, shops and schools, has been damaged and destroyed by airstrikes and ground war. For too long all parties to this conflict have been allowed by the international community to show an unashamed contempt for human life. More than 1,000 children have been killed or injured – a number that rises every day.

Many of the families I’ve met here have asked me why Yemen has been abandoned to its fate. The truth is I am often left wondering the same thing myself. I cannot tell them that Yemen is not popular with opinion-formers and leaders, not a cause célebre. What keeps me awake at night, besides the unnerving hum of fighter jets and crackle of artillery fire, is the fear that the world won’t understand the tragedy that is unfolding here until it’s too late.