AN Egyptian startup is aiming to turn more than 5 billion plastic bags into tiles tougher than cement as it tackles the twin problems of tonnes of waste entering the Mediterranean Sea and high levels of building sector emissions. "So far, we have recycled more than 5 million plastic bags, but this is just the beginning," TileGreen co-founder Khaled Raafat told Reuters. "We aim that by 2025, we will have recycled more than 5 billion plastic bags." At the company's factory, on the outskirts of Cairo, workers carry large barrels loaded with mixed plastic waste to be melted down and…