http://trak.in/tags/business/2016/08/19/no-custom-duty-consumer-electronics-mobiles/
http://dgft.gov.in/Exim/2000/NOT/NOT16/NotificationNo. 22(E).pdf
http://dgft.gov.in/exim/2000/Exemption_Order,_1993.pdf
from the Above I understood that, upto Rs. 50k, no customs duty. I may be corrected if I am wrong.