Chek Lap Kok Airport was designed as a replacement for the Kai Tak Airport, built in 1925. Located in the densely built-up Kowloon City District with a single runway extending into Kowloon Bay, Hong Kong Airport had turned on the runway lights for expansion to cope with steadily increasing air traffic. By the 1990s, Kai Tak had become one of the world's busiest airports, being a major hub for multiple passenger airlines along with a major cargo and maintenance hub – it far exceeded its annual passenger and cargo design capacities, and one out of every three flights experienced delays, largely due to a lack of space for aircraft, gates, and a second runway. In addition, noise mitigation measures restricted nighttime flights, as severe noise pollution (exceeding 105 dB(A) in Kowloon City) adversely affected an estimated 340,000 people. A 1974 planning study by the Civil Aviation and Public Works departments identified the small island of Chek Lap Kok, off Lantau Island, as a possible future airport replacement site. Far from the congested city centre, flight paths would be routed over the South China Sea rather than crowded urban areas, enabling efficient round-the-clock operation of multiple runways. The Chek Lap Kok (CLK) airport master plan and civil engineering studies were completed between 1982 and 1983, respectively. However, in February 1983, the government shelved the project for financial and economic reasons. In 1988, the Port & Airport Development Strategy (PADS) study was undertaken by consultants, headed by Mott MacDonald Hong Kong Limited, reporting in December 1989. This study looked at forecasts for both airport and port traffic to the year 2011 and came up with three recommended strategies for overall strategic development in Hong Kong. One of the three assumed maintaining the existing airport at Kai Tak; a second assumed a possible airport in the Western Harbour between Lantau Island and Hong Kong Island, and the third assumed a new airport at Chek Lap Kok. The consultants produced detailed analyses for each scenario, enabling the government to consider these appraisals for each of the three "Recommended Strategies". In October 1989, the governor of Hong Kong announced to the Legislative Council that a decision had been made on the territory's long-term port and airport development strategy. The strategy was to be adopted that included a replacement airport at Chek Lap Kok and incorporating new container terminals 8 and 9 at Stonecutters Island and east of the Tsing Yi island, respectively. In the PADS study, the consultants advised that the earliest the airport could be opened was January 1998. However, in reaching the government's decision, this date was changed to January 1997, six months before the handover of Hong Kong to China. Construction of the new airport began in 1991. As construction progressed, an agreement was reached with China that as much as possible of the airport would be completed before the handover to China in July 1997. Former British prime minister, Margaret Thatcher, opened the Tsing Ma Bridge, the main access to Lantau Island and the airport and its supporting community in April 1997. Soon after, the airport itself opened in July 1998. Hong Kong International Airport was built on a large artificial island formed by flattening and levelling the former Chek Lap Kok and Lam Chau islands (3.02 square kilometres (1.17 sq mi) and 0.08 square kilometres (0.031 square miles) respectively) and reclaiming 9.38 square kilometres (3.62 square miles) of the adjacent seabed. The 12.48-square-kilometre (4.82 sq mi) airport site with its reclamation, added nearly 1% to Hong Kong's total surface area, connecting to the north side of Lantau Island near Tung Chung new town.