Issues With Blouses

Those extra loops are easier to implement (with just hand sewing) than adding elastic to the sides of the blouse. Clever
I have a sewing machine, and had added elastic to the sides of a couple of blouses, and the waist of my very comfortable jeans. If OP is in India, there are tailors who can do this rather quickly, for not too much cost.

 

@Amulet,
Post the picture showing how/where the elastic was added and how it looks. If it works, I would like to give it a try.

 

I dont have any pictures to show you... but then there are plenty of youtube videos on the how-to. Here is one for jeans. Blouse elastic is just a variant of the same scheme - the elastic is hidden in the folded hem. I had used two pieces of elastic (one on each side of the back loop-hook).

[If the jeans' waist is too small, there is a different video that show how to slit the waist on both sides, and add elastic waist extenders. If a kurthi is worn over that, the sewing job is hidden ]