Airtel is giving high speed internet just in 2G plan. To achieve that
First activate 3G on your Airtel Number by dialing 121.
It will take some time to activate and you will get a confirmation message.
Make a recharge of internet plan of 2G. As Rs 19/ 200 MB 3 days.
Then select your network as WCDMA/UMTS only. If there is no Airtel 3G Network then
Select Idea/ Vodafone 3G Network manually.
It will show Roaming but you connect.
and surf the internet at very high speed.
I am using this trick at Rs 0/ balance.