You don't have to hold the territory to destroy those factory's, a prolonged battle or bombing campaign would reduce them to rubble.
I have a very good idea just how hard it would be to hold a chunk of India simply on population stats. You would have to be at war with India for a long time before you would see any results in attrition, most likely not in your favor without a significant technology advantage.
Ithekro...
Chile 7 factories (1/1/192
2 - Santiago
2 - Talcahuano
1 - Valparaíso
1 - Antofangasta
1 - Concepción
Looks good except I'd maybe swap Antofangasta with Vina del Mar.
As for my own factory list its in the works, along with a totally useless list of army, airforce (based on current mechanized and air squadron levels) and civilian factorys (based on population).