0608 GMT January 27, 2020
Smoke swept through the airport's Terminal 2 building after a fire broke out in the departure hall, spurring authorities to seal off the area.
Three people were sent to hospital for smoke inhalation, the Singapore Civil Defense Force (SCDF) said on its Facebook page.
"A small fire occurred at the departure hall of Changi Airport Terminal 2. The fire has been extinguished by SCDF," the Singapore Police said in a statement.
Police said the fire alarm was activated at around 5:40pm (0940 GMT) as smoke poured from air vents, sparking an evacuation order and closure of the terminal.
Passengers on flights departing from the terminal on Tuesday evening "should expect significant delays," airport management said.
Singapore Airlines said it was "working closely with the airport authority and various agencies to ensure flights can be resumed in the shortest time possible".
An AFP reporter at the airport said the scene was generally calm as the departure and arrival halls were evacuated. Airport staff were also seen leaving but there was no panic.
More than 58. million international passengers passed through Changi Airport last year. The airport serves more than 100 airlines flying to some 380 cities worldwide.