 When the GST was introduced in 1994, the work scope of the CED was expanded.The red and green channel customs system was implemented in 1991 at Singapore Changi Airport and at sea checkpoints.The CED was located first at Cecil Street from 1910 till 1932 and later the White House at Maxwell Road from 1932 until 1989 when it moved to World Trade Centre (now HarbourFront Centre).