Add Chattogram (Bangladesh) to your list and use my-locations table to visually convert it's time to another timezone or city time.
Mouse over the colored hour-tiles and glance at the hours selected by the column.

Current time zone for Chattogram (Bangladesh) is Asia/Dhaka, whose offset is GMT+6 from Greenwich Mean Time (GMT).

The IANA timezone identifier for Chattogram, Bangladesh is "Asia/Dhaka"

It currently does not observe Daylight Savings Time.