Using satellite images to tackle modern slavery across South Asia's 'Brick Belt'

 Brick kilns
12 Mar 2018 12:41:00.190

PA 41/18

A group of researchers have come up with the first ever accurate estimate of the number of brick kilns across the South Asian ‘Brick Belt’ using satellite imagery from Google Earth – a major breakthrough in the fight against modern slavery.

Using high resolution satellite images, experts from the Rights Lab at the University of Nottingham, were able to make a credible estimate of the number of brick kilns across the ‘Brick Belt’ using a straight forward and easily replicated method.

The ‘Brick Belt’ region stretches across parts of Pakistan, India, Bangladesh and Nepal.

The team estimate that there are currently 55,387 brick kilns along the ‘Brick Belt’. This is particularly shocking, as kilns are notorious sites for modern day slavery. The full findings of the study are published in the ‘ISPRS Journal of Photogrammetry and Remote Sensing’.

Not only will this method help to calculate the scale of modern slavery in these areas, it will also help to identify the wider impact of slavery, for example, the environmental impact of these sites.

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Understanding where slavery is taking place is a vital step towards helping to achieve the United Nation’s Sustainable Development Goal target 8.7 – which aims to eradicate modern slavery by 2030.

Although there have previously been regional estimates of the number of brick kilns and thus slaves working within them, the full scale of the number of brick kilns and by proxy, slavery, was unknown, making action from the appropriate agencies virtually impossible.

Now, this research provides data to help NGOs and governments fight modern slavery.

Previous research points to the ongoing and widespread exploitation of brick kiln workers, with many trafficked into situations of bonded labour slavery. The workers are mostly from socially excluded and economically marginalised communities.

There are different types of brick kilns around the world, however there is one dominant type that can be found in the ‘Brick Belt’: the large oval kiln known as the Bull’s Trench Kiln. As the brick kilns are so large and distinct in shape, they can be identified in satellite images.

In this study, brick kilns were identified by experts and also citizen scientists, using the most recent satellite data from Google Earth. The locations of the kilns were then mapped.

To get an estimate of the number of kilns across the entire brick belt, the team used a sampling approach. They used a probability sample of 100km2 square cells and identified the kilns present in each. The average density of kilns was then then scaled up over the region to make an estimate of the total number of kilns it contained.

Dr Doreen Boyd from the Rights Lab, the lead researcher on the study, says: “Accurate information on slavery activity is not easy to come by and is one of the biggest barriers in the fight against slavery. Building on previous work we’ve carried out, we wanted to find a way of calculating the number of brick kilns on the ‘Brick Belt’, which is an area notorious for using slaves, so that we can help to provide a clear picture of the true scale of the problem.

“We cannot successfully fight this abhorrent industry if agencies don’t know what resources they need to do so. This calculation is just the first step in helping agencies worldwide in preparing action plans on how to tackle the problem. There is a long way to go, and in our next step we will use artificial intelligence. In the meantime we hope that this initial work is a small step towards achieving freedom across the globe for everyone."

Dr Boyd talks more about this breakthrough in a new podcast episode of the Rights Track, available here.

The report Slavery in Space: Demonstrating the role for satellite remote sensing to inform evidence-based action related to UN SDG number 8 be found here.

The Rights Lab is a University Beacon of Excellence that brings together over 100 scholars to deliver research that helps to end global slavery by 2030.

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Notes to editors: 

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Story credits

More information is available from Dr Doreen Boyd from the
School of Geography at the University of Nottingham
, at

Charlotte Anscombe – Media Relations Manager (Arts and Social Sciences)

Email:  Phone:+44 (0)115 74 84 417 Location: University Park

Additional resources

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