Many believe that technology was not advanced in India, and was all imported from Europe. On the contrary, science in Ancient India was a beacon of knowledge for the rest of the world. Here is an example of Zinc Production at Industry level by India, when Europe hardly had any clue:-
The difficulty in Zinc production arises from its close melting and evaporation points. It melts at 950 deg C, and evaporates at 1000 deg C. While all other ores are dealt with by heating the ore from the bottom and then extracting the metal, this cannot be done for Zinc. when you heat it from bottom, the liquid goes on top and evaporates as temperature touches 1000 C.
Indians were clever to supply the heat from the top, and give a cooling platform for collecting molten drops of zinc! So the moment Zinc melts, it is collected from the bottom and solidified.
The Iron pillar of Delhi still stands as a marvel for advanced Chemistry, and Scientists are yet to figure out how to make a rod that will not rust away!
The Technology of spirituality was the driving force behind these and many more discoveries, including Medicine and Astronomy. Check out this series of videos for more details.