On the first Tuesday of this month, Saddam Hussein Abdu al-Burai said goodbye to his wife, pregnant with their first child, and left home to make the 10km journey to a Yemen snack-food factory inside an industrial complex in the Alnahda district of the capital, Sana’a. It was his first day at work but at 9.30am, barely two hours after he had begun manually counting the potato bags inside the steel girder compound, a Saudi-led airstrike began.

Burai was killed on the spot along with six other men and three women. The attack on the potato crisp factory came during the first airstrike by the Saudi-led coalition against Houthi rebels since the collapse of UN-brokered peace talks earlier this month.

A three-month hiatus following the April ceasefire, which was often violated but had brought some peace to Sana’a, effectively came to an end, hostilities resumed and Burai, who had no connection with politics or the war, was one of the first victims of the collapsed talks.

The Saudi-led campaign, backed by the UK and US and launched in March 2015, is aimed at reinstating the ousted president, Abd Rabbu Mansour Hadi, who first fled to the southern city of Aden before going to Riyadh in March 2015. Houthi fighters, belonging to the Zaydi sect of Shia Islam, are allied with the former president Ali Abdullah Saleh and control Sana’a and vast swaths of territory in western Yemen.

The Saudi coalition has been criticised by the UN and human rights groups for airstrikes that hit civilian targets. In the case of the blast that killed Burai, a Houthi-controlled military maintenance camp was located approximately 20 metres south of the crisp factory, separated by two large walls. The airstrikes, instead of hitting the military camp, struck the middle of the factory, where about 60 people were working the morning shift.

Abdulrahman Saleh Abdu Salah, a 26-year-old electrician, was charging his mobile phone in the manager’s office when a huge blast rocked the building. He was one of the lucky ones. “Suddenly we heard a massive explosion and everything started to fall on us, even the wall fell on us,” he told the Guardian. “I stood up and went back to the factory, I saw everyone was scattered on the floor and some people were killed on the spot because of shrapnel and the place started to burn.”

“I saw one of my colleagues near the machine I was fixing and he was jumping and shouting out in pain – he was the only one I could help and I took him outside. Minutes later the whole place was on fire and people were killed and their bodies were burned.”

Salah said he thanked God that he survived the attack, which left many of his friends dead. His best friend, Mostafa Aqeel, was among 13 workers injured and is still in hospital. Five are in intensive care and one is in a coma. Salah said he did not understand why the Saudi-led coalition targeted civilians.

“Why did they target us?” he asked. “It’s a snack-food factory. No weapons, no bombs, no fighters are inside. Only men and women workers.” The factory, which was established in 1985, has now closed down.

Both sides in the conflict have since escalated their attacks, with a recent airstrike by the Saudi-led coalition hitting a hospital supported by Médecins Sans Frontières in the Abs district of Hajjah governorate, in north-west Yemen. That attack, the fourth against an MSF facility in less than a year, killed at least 11 including an MSF staff member. It prompted MSF to announce earlier this week that it would withdraw from six hospitals in northern Yemen.

Houthis have retaliated by firing missiles across the border, which has also resulted in civilian deaths.

Juan Prieto, MSF Yemen’s head of mission, said it has become difficult to operate in Yemen. He condemned the attacks on the hospitals and said he did not understand why they kept happening. The coalition has accused Houthis of hiding military equipment and personnel in public places such as schools and hospitals. A recent school attack in the Haydan district in northern Saada governorate killed 10 students who were all under 15.

“In the facilities that we have been running our services, we can guarantee that there has not been any military activity,” he told the Guardian by phone from Sana’a. “We have been following all the rules that [the Saudis] have set up and the attacks continue happening, we are wondering why. There is a lack of respect.”

Prieto said the situation in Yemen was deteriorating, especially people’s access to food and water. “The system cannot cope with the need at all,” he said. More than 6,000 people have been killed since the conflict began – half of them civilians and more than 1,100 of them children, according to the UN.

The UN chief, Ban Ki-moon, called on both sides three times last week to end the violence. “Civilians, including children, are paying the heaviest price in the ongoing conflict, as civilian infrastructure, such as schools and hospitals, continue to be hit,” he said.

Maha Nagi, a 30-year-old based in Sana’a who works in the humanitarian field, said most people had lost their jobs and had difficulty coping with the basic cost of living, while others had been displaced and struggled to find a place to sleep. She said that since the collapse of the peace talks there have been five to 10 airstrikes in Sana’a and its vicinity every day.

“What is new this time is that they are not only targeting military places but they also hit family houses,” she said. “I blame all parties because they only care about victory and defeating others to win more power and I blame Saudi Arabia for intervening and making it worse. They target every place in Yemen and are killing innocent people. They don’t make exceptions, they target even schools and hospitals.” Twitter users have been using #NotATarget to highlight attacks on civilian places.

“It’s a really catastrophic situation in Yemen. We want to be safe and not be killed by Saudi jets,” Nagi said. She said healthcare was bad and there was no public electricity in Sana’a. “You can either use a generator or solar power.”

Sana’a-based political analyst Hisham Al-Omeisy said airstrikes in recent weeks had become more indiscriminate. He said that while the Houthis were “guilty of hijacking and mismanaging the state”, it was the Saudi-led coalition that had “held the whole nation hostage to the current conflict and [had] been collectively and indiscriminately punishing”.