Covering of a woman’s chest comes under وَ یَحْفَظْنَ فُرُوْجَھُنَّ directive, which has been discussed at length in the above video. The directive of khimar is to cover the embellishments on this area, this covering can be done in any way other than khimar, as long as the spirit of the directive is maintained. However, any loose shirt which kills the spirit of وَ یَحْفَظْنَ فُرُوْجَھُنَّ directive would be considered as an against the directive attire.