BSNL launched pay per second postpaid plan (Plan225) for its subscribers.
“Per second billing will be an advantage for customers. BSNL has introduced per second pulse in postpaid plan 225. ISD calls are now available on per second pulse making it more affordable and attractive,” BSNL CMD Kuldeep Goyal said.

BSNL Plan225 Postpaid pay per second [...]

BSNL Pay Per Second Plan Details:

Pay per second Voucher Price: Rs. 45/- Indian Rupee (INR) except West Zone**
Valid for 365 Days
Talktime: 0
Call Rates
BSNL to BSNL: Local and STD at 1 Paise/Second
to other Networks: Local and STD calls at 1.20 Paise/Second
SMS and ISD rates as per Normal Prepaid Plan

** [...]

BSNL announced free roaming mobile services in seven north-east states (Assam, Arunachal Pradesh, Meghalaya, Manipur, Tripura, Nagaland and Mizoram)
BSNL free roaming will be available for both Prepaid and Postpaid customers under some terms & conditions starting from 1st September, 2009.
During roaming same local tariff plan will be applicable for outgoing call, SMS and GPRS and [...]