According to my research, it seems that Airtel provides decent speed or, at least, this is what users which have the same product said. But going into a more technical answer I would recommend disabling Firewall (use this command clicking
netsh firewall set opmode disable) or disable Internet proxies if you have any (
Start Control Panel ?> Internet Options > Connections > Lan Settings > Uncheck Use a Proxy Server). Then try and browse through the Internet again. One more problem causing troubles is your antivirus solution. Try turning it off during the time you perform tests in order to see the result and perform a network speed test using Speedtest website for more accurate results.