The Thames Tideway Tunnel is a major infrastructure project in London designed to improve the city's sewage system. It aims to reduce the overflow of untreated sewage into the River Thames during heavy rainfall, which can lead to environmental pollution and health risks. The tunnel will be approximately 25 kilometers long and is expected to handle up to 1.6 million cubic meters of sewage. Construction of the tunnel began in 2016 and is scheduled for completion in 2025. The project involves digging deep underground and connecting various existing sewer systems to the new tunnel. Once operational, the Thames Tideway Tunnel will significantly enhance the water quality of the Thames and support the city's growing population.