Why are Tata cars so cheap in India?

Few things I will share that a Tata man told me.

1. Tata make its own steel here. Due to same reason the body of tata cars is very solid and durable.
2. Tata makes the parts of its cars as many as possible. Against it, other car companies buy different parts from different platforms and produce a mix veg type vehicle.
3. Tata makes here use of indigenous technology as much as possible.