"With this pack, Airtel prepaid mobile customers can now get up to 30 days of free incoming calls while travelling to Bihar, Jharkhand, Uttar Pradesh, Uttrakhand and West Bengal (except Kolkata) on a recharge of Rs. 21," Bharti Airtel said in a statement.
Airtel's Delhi customer at present are charged Re 1 for incoming calls, Re 1 for local outgoing calls and Rs. 1.5 paise for STD calls on roaming, the company said.
The company has also announced the launch of high quality voice service for its subscribers in Kenya, Rwanda, Malawi and Nigeria in the African subcontinent.
"Airtel becomes the third operator to launch a mobile HD voice service in Africa. Further launches will be scheduled in 2013," the company said in a statement.
With HD voice, customers can talk normally and be heard clearly, without having to raise their voice, even in noisier environments.
"Surveys confirm that customers place a high value on HD voice," Airtel Africa Chief Marketing Officer Andre Beyers said, adding, "the new service will enrich end-user experience for Airtel subscribers".
Mobile HD voice enables high-quality voice calls because it reduces background noise often heard on a regular call.
It is based on AMR (Adaptive Multi Rate) wideband technology (W-AMR) which operates with nine different bit rates, providing high-quality voice calls.
Compared to the current narrow-band speech codec device, the W-AMR speech-compression algorithm doubles voice bandwidth and produces better results.