You can use TATA Docomo to call your friend @ 1p/s
However Airtel is world's 5th Largest Telecom Company. And I don't find a price rise of 10% a big deal.
This is far more worth worrying. I expect local call tariffs to rise sooner or later. And hence, as a precaution, I've got my family members postpaid plans or rate-cutter packs with long validity.