Update: Airtel's 3G service is now up. The company hasn't yet issued statement on reasons behind the network outage.
Original story:
Airtel's 3G network seems to be down in Delhi. A lot of customers have already complained (on Twitter) about not being able to access 3G network. Some users have also complained about call fails and GPS being down.
We've tried to contact the Airtel customer service, but have been unable to reach. Meanwhile, Airtel has responded to some users saying that it is working towards restoring data services at the earliest.