A Mexican entrepreneur began melting discarded plastic into wall and roof panels; within three years his startup had built 500 rooms and secured contracts for 300 homes

• The process, developed in 2013 by social enterprise EcoDom in Puebla state, turns melted plastic waste into strong wall and roofing panels.
• Within three years of starting operations, the company had built 500 rooms for municipal housing programmes and won public contracts to construct 300 c