Blouse was (yes, it was) essentially a generic garment to conceal the basic parts of female body. Still in some parts of the Indian state, women wear no blouse - however may be the age.   Today it has become an important factor in expressing the fashion. The fundamental aspect of concealing has gone, and publicity aspect has taken its place. You may be stunned or shocked, amazed or surprised, pleasantly wondered or perfectly agreed, may be not even noticed or casually overlooked, or even purposefully observed and repeatedly talked about it - whenever you see a female wearing different varieties of choli or blouse on the street, office, function or any gathering.
The T Shirt replaced the blouse to an extent as jeans replaced the saree or other dress material - particularly for teenagers and to an extent in working women.
The style, the design and cut of the choli speaks about the lady's attitude. So the earlier ambiguity is replaced by the stern attitude.