A young scientist has developed a white powder which gives waste soil concrete-like properties. Gnanli Landrou grew up in Togo, helping his neighbours dry out soil to make bricks, and his big dream is to help people like them build stronger, cheaper, houses. But the European building industry is also excited about his new, low carbon building material. We talk to Gnanli about his ambitions for this extraordinary powder, and meet the Swiss architect who is about to build a luxury apartment block with it. Presenter: Myra Anubi Reporter: Jo Mathys Executive producer: Tom Colls Editor: Penny Murphy Image: Gnanli Landrou