Pooran admitted the charge, which deals with a breach of level 3 of the ICC's Code of Conduct, and accepted the sanction proposed by match referee Chris Broad. He had violated Article 2.14 of the code, which relates to "changing the condition of the ball" after video footage showed him scratching the surface of the ball with his thumbnail.
Pooran will now miss West Indies' three-match T20I series against Afghanistan and the first game of their subsequent three-match series against India. He will also have five demerit points added to his record. The earliest he will be available to play for West Indies is the second T20I against India, on December 8 in Thiruvananthapuram.
The charge was levelled by on-field umpires Bismillah Shinwari and Ahmed Durrani and third umpire Ahmed Pakteen as well as fourth umpire Izatullah Safi.
Calling his act "an extreme error in judgement", Pooran said he accepted the penalty while promising this incident was a one-off.
"I want to issue a sincere apology to my teammates, supporters and the Afghanistan team for what transpired on the field of play on Monday in Lucknow," Pooran said in a statement issued by Cricket West Indies. "I recognise that I made an extreme error in judgement and I fully accept the ICC penalty. I want to assure everyone that this is an isolated incident and it will not be repeated. I promise to learn from this and come back stronger and wiser."
West Indies had completed a 3-0 sweep against Afghanistan in the ODIs, winning the third game by five wickets with eight balls to spare. Pooran had a successful series with the bat, and was the Man of the Match in the second game for smashing 67 off 50 balls. He was likely to have kept wickets for West Indies in the T20Is, but they have Denesh Ramdin in the squad as back-up, and the 34-year-old will now get to add to his 68 T20I caps, the last of which came a year ago, in November 2018.