Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron, and other ingredients. Materials used to manufacture cement include limestone, shells, and chalk combined with shale, clay, slate, silica sand, and iron ore. These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement. Cement mixed with sand, gravel, and water makes up concrete. Because of their abundant resources, easy operation, durability and versatility, cement and concrete are the most widely used construction materials. The soaring population growth and urbanization expected over the next few decades worldwide suggest that cement demand will keep growing. Globally, each year over 4 billion tonnes of cement is produced. While it helps to pave the way for modernization, the cement manufacturing comes with adverse impact on the environment, climate change and health: