The Rent/Buy calculation indicated here is definitely not applicable to a diverse, big country like India where even within in tier II cities the cost of house or rent vary widely based on location, facilities, demand / supply, etc. Many parameters that to be considered can be selected based on your actual experience to arrive at critical decision for the serious buyers / renters by following the link which definitely provides a more realistic calculations. So I suggest all readers to see INTERACTIVE RENT / BUY calculations by NY Times at the following link.
