According to the Guardian*, India is the second-largest brick producer in the world after China – contributing around £3bn to the country's economy every year. Delhi-based Centre for Science and Environment points out the fact that, despite its size, the brick kiln sector of India remains largely unorganized. "The kilns themselves are mostly illegal, so keeping track of them is hard and they keep no records," said Chandan Kumar, ActionAid's national coordinator for the Bonded Labour Eradication Programme.

Even though there are no official figures on the number of people employed to cut, shape and bake clay-fired bricks, mostly by hand, the brick industry is estimated to employ around 10 million people. According to Unicef, in particular, “the brick kilns workers are recruited arbitrarily by local contractors. As the payment is made to the head of each family based on the number of bricks produced, it is not uncommon to find children involved in the process to maximise income.

At the sites, young boys and girls can be seen standing in thigh-deep mound of water, clay, straw, ash and coal dust, kneading the mix. They are also involved in transporting moulds to the baking centre and in drying bricks under the sun. The brick kilns owners say they are helpless if parents involve their children in the work”.

“It's modern-day slavery,” says Andrew Brady, of Union Solidarity International(USI), a UK-based NGO that has been campaigning to improve the brick labourers' conditions over the last two years. “Entire families of men, women and children are working for a pittance, up to 16 hours a day, in terrible conditions. There are horrific abuses of minimum wage rates and health and safety regulations, and it's often bonded labour, so they can't escape.”

*Blood bricks: how India's urban boom is built on slave labour, Oliver Wainwright, 8 January 2014