Question

What change were noticed when the Indian system of vocal music interfaced with the Arab Iranian and central Asian traditions?

Answer 1

It started in Mughal times, when the singing was done at Akbar's court, the combination of these instruments was used. The music which was popular at that was known as Hindustani classical music. 

Answer 2

With these countries new instruments were introduced. And with that Indian started to use different instruments together and formed a new music which was started in about Akbar's time.