I could be wrong, but I don't think there is a nylon backpack manufacturer in India. Cotton, jute or leather though, are Indian materials they make bags with.
Here is a listing of Indian bag manufacturers (in Asia, it seems nylon backpacks are made in China, Taiwan and Thailand). You could ask these manufacturers and find out or ask for a referral. I could get you Chinese and other Asian contacts for the standard backpack types. For instance, Jansport is made in Taiwan, as I recall from looking for you before.
I have a theory about not wanting to swim up stream.
If it looks like I am the only one swimming then maybe I am in the wrong river.
It looks like India is sort of out of the game. They so far do not have any backpacks for sale and the ones may be from Taiwan?
I am sure they make some backpacks here somewhere. But it does not seem obvious so far. This is a big country. I know that in La Paz, Bolivia they have a market that has all the raw material type pieces that you can buy to manufacture backpacks. In fact... hehehe they also sell the brand name tags so you can add to the bag. This is specifically so they can make copies.
But in the end a good supply of parts and a good supply of labor is needed. So it looks like China, Taiwan and Thailand become more interesting and India become less. I am wondering about whether this is about them export them to me, or me going and importing them.
I still have Peru, Ecuador, and Bolivia on my list. But then China, Taiwan and Thailand