Bharti Airtel hikes call tariff by 20% in six circles

[Topweb]

What will happen to the existing customers? Will I get 6 month notice before tariff on my Airtel number is changed? IIRC, telecom companies were required to give a 6 month long notice to existing customers before moving them to a different plan.Looks like telecom companies are having to pay bigger amounts as bribes.