With the participation of 16 teams, the T20 World Cup 2021 consists of the following stages - the qualifying stage and the super twelve.
There are eight teams that don't have to play the qualifying stage for the super twelves and are divided into two groups - Group 1 and 2. The other 8 teams are divided into two groups, Group A and B and two teams from each of the groups-- 1 and 2, will qualify for the super 12 groups.
Group B consists of Bangladesh, Scotland, Oman and Papua New Guinea. Group A consists of Sri Lanka, Ireland, Netherlands and Namibia.
Initially, ICC's schedule for the tournament presented that Bangladesh and Sri Lanka only have to qualify to finish the group as B1 and A1 and can join the super-12 group 1 and group 2 respectively. That meant their standings in the group didn’t matter to decide their future.
As the qualifying stage is halfway through, Bangladesh seems to have high chances of finishing as a runner-up of group B. But ICC have declared a change in the policy of selecting the group leaders, and it will be decided by the standings. That means if Bangladesh stands as the runner-up of the group, they will enter the super-12 group 1 as B2.
This change after matchday-3 of the group stages may lead to some problems. The spectators who bought the tickets according to the schedule that presented Bangladesh as A1 will probably have to enjoy the game of some other team on that particular date.
The tables have turned for the playing teams as well. Bangladesh may have to come up with a completely different strategy, compared to the one they were preparing considering the opponents they were initially supposed to face.
Changing the rules after a tournament has begun is in no way a professional decision by ICC and the critics and fans alike are critical about this.