Taiz, Yemen - Last month, Hani Mansour took his wife, who was expecting their first child, to the Republican Hospital in the city of Taiz.

After spending hours at the state-run hospital, Mansour's wife gave birth. Mansour was overjoyed to hear the news, but was shocked when the doctor told him that his son needed to stay in an incubator because his lungs were not fully developed.

However, because of Yemen's ongoing civil war in which the Houthi rebel group is besieging Taiz, the Republican Hospital has no oxygen cylinders, and its incubators do not work.

"I tried to move my child to al-Hikma private hospital, but there were no oxygen cylinders there either, so my child died five hours after his birth," Mansour told Al Jazeera.

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As the war in Yemen continues to rage, 37 of the 40 hospitals and medical institutions in Taiz, Yemen's second city, have closed. Only the Republican and al-Hikma hospitals have incubators, but because both hospitals usually lack oxygen supplies, the incubators do not work regularly.

"Around 20 oxygen cylinders arrived at the hospital in the last two weeks," Dr Rania Mohammed, the supervisor of the incubators department at the Republican Hospital, told Al Jazeera. "But these cylinders are not enough, as some of the children need to stay in the incubators for several weeks and sometimes for two months, and these cylinders only last for a few days."

Mohammed added that power cuts further complicate the use of the incubators: "The fathers of the newborn children have to bring generators to the hospital to turn the incubators on."

That was the case for Ridhwan al-Ashari, whose wife gave birth at the Republican Hospital on January 13. The child was in dire need of oxygen, and although there were oxygen cylinders in the hospital, there was no fuel for the generator powering the incubator.

"I brought my own generator from my house and I turned the incubator on. But after two days, the oxygen cylinders ran out, and my child needed to stay in the incubator for two months. So after all these efforts I made, my child died," Ashari told Al Jazeera.

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Abdul Hakeem al-Ameen, a doctor on the medical committee in Taiz that is responsible for distributing medicine to hospitals, said that 25 people died last month because of the lack of oxygen cylinders in the city, including 13 children. An additional 30 people died in December, he said, most of whom were children.

"There are around 600 patients waiting for surgical operations, and they cannot do them because of the lack of oxygen. So some of those patients may die if they do not do the operation," Ameen told Al Jazeera.

The Houthi rebel group prevents the import of basic commodities, as well as medicine, propane, and oxygen cylinders, to besieged areas of Taiz.

According to Mohammed, the only way oxygen cylinders can be brought in is by smugglers, who carry goods on the backs of camels on a road cutting through the mountains.

The oxygen cylinders are transported from Aden province to Talooq village, only four kilometres from Taiz. Then, the smugglers take the oxygen cylinders to Taiz's al-Maradei area.

Mohamed Moqbel, 45, a camel owner, is one of these smugglers. He told Al Jazeera that he started this work last month.

"Every morning, I go to Talooq with around 20 camel owners to meet doctors. Then they give each camel owner two oxygen cylinders, and we leave Talooq towards the city. After four hours, doctors meet us in al-Maradei in Taiz to take the cylinders," Moqbel said.

"I get 5,000 rials [$23] for each cylinder, and my camel carries two cylinders at once. So it is profitable work for us, as we get 10,000 rials [$46] a day, but sometimes we do not find cylinders to smuggle."

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Moqbel said that he is very proud of his work as an oxygen smuggler, because he is helping patients in the besieged areas. The smugglers also carry medicine and other commodities.

But Abdul Kareem Shamsan, the head of the Taiz-based Humanitarian Aid Coalition, a local coalition of aid organisations, said that the oxygen cylinders smuggled into Taiz "only cover less than 15 percent of the total need, and the casualties because of the lack of oxygen cylinders are increasing every day".

He said that each cylinder, with the added price of transportation, now costs 15,000 rials ($70), compared with only 3,000 rials ($14) before the siege began.