The Pakistan Super League has been suspended with "players not in the right mental state" after seven cases of coronavirus were reported.
The decision to halt the Twenty20 competition was made after a meeting between PSL officials and team owners.
"Players were very nervous, anxious and apprehensive," Pakistan Cricket Board chief executive Wasim Khan said.
England and Quetta Gladiators batsman Tom Banton said he was "feeling OK" after testing positive on Tuesday.
After three more cases overnight on Wednesday, Khan says he suggested suspending the tournament for five days before making a firm decision on the postponement, but the "majority of players" did not want to continue.
"The franchises felt very uncomfortable, as we did, to put the players under any additional risk when there's no need to do it," the former Warwickshire cricketer added.
The 2020 edition was suspended at the play-off stages in March following an outbreak of the coronavirus. It was completed in November.
Khan hopes to complete this season's competition - which started on 20 February - by the end of 2021.
"We want to continue and finish PSL 6, as we did with PSL 5 when we found a window and finished those matches," he said.
"As a nation and the PCB we remain resilient that, with the support of the franchises, to make sure we can complete the remaining games before the end of the year.
The PCB said it would now "immediately focus on the safe and secure passage of all participants", as well as arranging repeat tests, vaccines and isolation facilities to the six participating sides.
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