Q: worked in uk now in india  how to access indian cellular network

Is your phone officially unlocked? If not, it won't work with any other sim other than one from the carrier your phone is locked to.

Contact O2, they offer official unlocking.

http://www.o2.co.uk/unlockmyiphone

But I believe the iPhone must be active on the O2 network

in the UK for O2 to process the request and that means physically in the UK