Abu Mahmud loads trash into a turquoise truck in Aleppo, seemingly oblivious to shells smashing into nearby streets as he makes a small dent in the mounds of refuse piling up in the battleground city.

With the battle for Syria's one-time commercial hub now deep in its third month, trash collection services have almost completely broken down in rebel-held areas and mounds of rubbish are rising in the streets.

The strategic northern city has become a main prize in the civil war as rebels fighting to overthrow the regime of President Bashar al-Assad push to create a buffer zone along the border with Turkey.

Rebel-held areas of Aleppo are targeted daily by Assad's artillery, tanks and warplanes, leaving buildings shattered and rubble piled everywhere.

As the battle for the city has rumbled on, the number of rubbish collection trucks has dwindled.

Piles upon piles of stinking rubbish cover the streets, from rotting food to bloody bandages and other grisly medical waste left near a hospital, attracting swarms of flies.

Some residents try to dispose of the trash by burning it, sending up waves of acrid smoke across Aleppo.

Abu Mahmud, who has worked as a rubbish collector for 23 years, does not seem perturbed by the shelling.

"We are working under the mercy of God," he said. "Is there anyone not in danger under the strike?

"No one dies except when his time is up," Abu Mahmud said.

The government pays his salary and he says he carries on with his job just to make a living, despite the daily hardships and the lack of staff and equipment.

"What can we do with our hands? We want trucks, trucks and workers," he said when asked about the large amounts of trash in Aleppo's streets.

Residents say the trash problem is getting worse and worse, and complain about the threat of disease.

One of them, Abu Mohammed, complained about the stench of the garbage, as he recalled better days when his city was clean and there were trucks and workers, among other services.

"We hope that they will remove (the trash), so no one becomes sick," said Abdullah, another resident.

A rusty white rubbish truck, its windshield missing and its hood bouncing up and down, backs up to a massive dump of smouldering refuse at Jisr al-Hajj roundabout before emptying a mix of trash and dark, foul liquid.

The site was not a dump before war came to Aleppo in mid-July, but now it is piled high with trash that is constantly burning, clouding the area with white smoke.

A young boy runs by the rubbish heap trailing a box on a string, trying to fly it like a kite.

Before, "about 110 trucks went out in Aleppo... Now, not even around 10 trucks, 20 trucks go out," said Hassan Hardan, the driver of the white truck, a job he has held for 13 years.

"The situation is very, very bad, because the trucks are being stolen, gunmen are taking the trucks," he said.

"And the diesel is stolen from the truck, they take the diesel from the driver by force of arms. This happened to me today," he said, adding that sometimes truck batteries are also stolen.

He still receives a salary from the government, but like Abu Mahmud, he does not specify how he obtains it, or if he has to cross the front lines to collect it.

"I hope that the country will become cleaner than this, and that the situation will improve, and that these problems will not remain, and that God will protect us," he said.