The solution is simple - use a better DNS server. One way of doing this is to change the network settings in your computer to use a static DNS. In linux, you edit /etc/resolv.conf. In windows this is done by editing Interface properties.
But this method did not suit me because there are multiple devices connected in my home network and I will have to change all of them. Also, devices come and go in our network (We have BYOD!). The way out is to change your modem settings so that your modem relays a different DNS than what Airtel gives you.
I have always liked Google public DNS -- I think because they have super simple IP addresses ;). I used it as my DNS Server.
I have a Binatone DT845W modem. So the steps below are for that modem.
Connect your modem in your browser. Usually modem IP is 192.168.1.1, so just point your browser to that address, provide your admin username and password.
Go to "Interface Setup" -> "LAN", there you can find a section called "DNS". Change DNS relay to "Use user discovered DNS". Fill in your favorite DNS server IPs, save the settings and your done.
Welcome to a better Internet :)
