Hong Kong authorities are exploring plans for a fourth cross-harbour tunnel to relieve heavy traffic and support the city's growth. The current three tunnels face persistent congestion. The idea follows shelving a massive HK$580 billion reclamation project near Lantau Island known as Kau Yi Chau. Assistant Commissioner for Transport Leung Sai-ho shared on a radio show that earlier, the government was confident about building a tunnel as part of Kau Yi Chau. But since the project's timeline is unclear, "we would like to be more flexible at this stage and see if we can find alternative routes," he said. Authorities will consider traffic demands and costs while planning. The abandoned Kau Yi Chau project aimed to create three artificial islands with homes for 550,000 people, a new business district, and links between Hong Kong Island and the northwest New Territories. It was paused to focus on the Northern Metropolis megaproject, targeting housing and technology near the mainland border. Now, the government is reevaluating how to ease cross-harbour transport with fresh options for a new tunnel.