The mobile call rates were increased up to 30 per cent on Wednesday. Some private companies hiked the rates of special tariff vouchers and reduced the promotional offers owing to heavy surcharge imposed on the telecom companies' spectrum.

The price increase will be extended to all the 22 telecommunication zones of India phase wise.

Airtel  reduced free minutes by 10 to 25 per cent and increased the price of special vouchers in the range of Rs.5 to Rs.15.

'We have only reduced the promotional benefits and free minutes on both acquisition and exiting usage. There is no change in the headline tariff,' an Airtel spokesperson said.

The Idea, Vodafone and Tata Docomo companies raised the voice call charges in circles.

The Reliance telecom raised the prices last September.