Inside the perilous brick-making factories of Bangladesh: Millions of workers face harsh conditions as they toil to keep pace with the country's breakneck construction boom Toiling under the baking hot tropical sun, these workers are carrying out back-breaking and exhausting labour in the most perilous conditions. Ranging in age from pre-teens to grandparents, they work long hours to churn out millions of bricks to fuel a construction boom that shows no signs of abating. The cities of Bangladesh - one of the world's most densely populated countries - are growing fast, and there's a never-ending need for cheap construction materials. Toil: Workers balance bricks on top of their heads in the shadow of a kiln at one of the country's estimated 6,000 brickworks, which are booming along with the densely populated country's rapid growth A young boy is covered in soot from working at a brick-making kiln: Working children are a common sight at brickworks as they regularly employ entire families - who often make their homes on site An old man sifts through broken fragments of brick: Brick-making provides a better income than agriculture or other jobs available in rural Bangladesh, but it is risky and often devastating to workers' health A worker's makeshift leather glove is complemented by a bandage around his finger: Accidents are common and workers have no protective gear, save for what they are able to cobble together themselves And in a country marred by underinvestment, bricks are the most efficient and widely used. With GDP growth of 6.3 per cent last year, Bangladesh is growing fast; each day new brick buildings are erected across the country, which is already home to 153million people. Dotted across the country are thousands of slender chimneys piercing the horizon above brick kilns which, according to the UN, produce some 12million bricks a year. However, the millions of workers who make the bricks face harsh and uncertain conditions. Brick-making provides a better income than agriculture or other jobs available in rural Bangladesh, but it is dangerous and often devastating to workers' health. Accidents are common and workers have no protective gear, save for what they are able to cobble together themselves. Massive industry: Dotted across Bangladesh are thousands of slender chimneys piercing the horizon above brick kilns which, according to the UN, produce some 12million bricks a year to feed a construction boom Back breaking: Workers carry stacks of bricks on their heads. Brick making in Bangladesh's estimated 6,000 authorised brickfields is still carried out according to a system that is some 150 years old Hewn from the earth: Sinewy men carry the tools they use to excavate the mud from which bricks are made School age: But education is a luxury for Bangladesh's rural poor, with children often earning their keep as soon as they can walk Health risks: Dust from the brick-making sites spreads on the wind to nearby towns and villages, clogging the lungs of young and old and generating health problems the country is ill-equipped to handle Brick making in Bangladesh's estimated 6,000 authorised brickfields is still carried out according to a system that is some 150 years old. The production process begins with workers hacking mud from the earth with picks and shovels. From the moment it is excavated the sun begins to dry it out so water must be constantly mixed in to keep it workable. Balancing the heavy loads atop their heads, workers must carry the raw mud to the brick making area, where skilled artisans shape it using brick moulds filled by hand. After pressing, each mould is emptied out and the bricks are left to dry in the sun before being taken to the kiln for firing. Working children are a common sight at brickworks as they regularly employ entire families - who often make their homes on site. School is a luxury for Bangladesh's rural poor, with children often earning their keep as soon as they can walk. Difficult conditions: From the moment the mud is excavated the sun begins to dry it out so water must be constantly mixed in to keep it workable Smoke spews from a kiln chimney: About half of Bangladesh¿s bricks are baked with the use of coal, making them the single largest source of greenhouse gas emissions in the country The fields are a major source of pollution in a country where environmental safeguards are scant A man stirs soup in a pot buried in the earth to conserve its heat: The millions of workers who make the bricks face harsh and uncertain conditions The fields are also a major source of pollution in a country where environmental safeguards are all but nonexistent. Dust from the brick-making sites spreads on the wind to nearby towns and villages, clogging the lungs of young and old and generating health problems the country is ill-equipped to handle. And about half of Bangladesh's bricks are baked with the use of coal, making them the single largest source of greenhouse gas emissions in the country, with several million tons emitted annually. The United Nations Development Project in 2010 launched a five-year project intended to green Bangladesh's brick-making industry. According to the news agency IPS, some experts say that a shift to greener kilns could slash the industry's carbon emissions by half.