This review paper will focus on the potential of using fly ash bricks in place of the generic clay bricks in terms of sustainability, properties, chemical composition and in terms of availability. Wastes produced daily in refineries and furnaces contain toxic elements. This paper will explore the possibility of reducing the waste and a step towards a sustainable building. Fly ash bricks are environment friendly, manufactured by hydraulic pressure machines, are 28% lighter than normal clay bricks and have a compressive strength greater than 40 MPa than normal bricks[1]. Due to its advantages over other building materials, the demand is constantly increasing in India, China and the other Asian Pacific regions, which in turn has created a global traction in the creation of fly ash bricks[2]. The construction industry is also one of the highest contributors to the country's CO2 emissions, accounting for 22% of the country's total annual CO2 emissions. The climate-friendly fly ash brick technology produces bricks without using coal. It has the potential to eliminate carbon emissions from the brick-making industry, which burns huge amounts of coal and emits millions of tons of carbon dioxide each year. In practice, the construction material uses a lot of virgin materials[3]. But the fly ash building material uses very minimal amounts of the same, 49% less, thus reducing the energy requirement to make these. This paper will focus on how fly ash incorporation (Massive volume fly ash concrete) is a sustainable option for building material, as well as a durable material for the same, absorption capacity, methods of making fly ash bricks, it's carbon footprint, how can they be made less toxic, the chemical composition compared to the generic clay bricks and how eco friendly it is. This paper studies the hazards in clay brick and advantages in fly ash brick extending with a comparative study on material properties of clay brick and fly ash brick.