Indica doesn't grow that far South. Look it up. Those are equatorial sativas that come from India. Indica doesn't mean India. Indica is a latin term for species identification and cannabis isn't the only indica classification --like the various types of indica rice.
Sativa (a similar latin term applying to various flora) was the bulk of cannabis (a more specific term I think you're looking for) until late 60s when real c. indica was imported. It's not suitable for hemp production as the stalks are shorter and the plant wider, thus taking up more growing space with less actual production. It also produces a mushier, less fibrous stem and is easier to break in high winds. What you want are 12' (arguably shitty) sativas for hemp production that flex in winds.
I'm under the impression it was first brought to US by African slaves and/or Spanish slave traders in the triangle trade because either through culture or lack of enough booze and wanting a buzz, it became popular with one another.
Interestingly when I was in Holland post ETS 20 years ago (honestly, to examine Dutch art and architecture --though I did try a gram of high test hash) I learned they only started using it because Hitler cut off their tobacco supply and for desire to extend the supply they cut it with --marijuana. Shitty Ruderalis to be exact. But that's how it happened there.
They have a library there dedicated to it, really informative and spent a couple hours perusing the older documents and artifacts which were of interest. 60s hippie trail was extensively documented.