For those interested, the reason places charge high rates on some exchanges is to cover risk. Here [1] is USD versus INR - look over the past year.

Look at USD to CAN or GBP or EUR on the same site for comparison.

Another factor is liquidity in the markets allowing those doing exchanges to offload unbalanced books efficiently.

[1] https://www.exchangerates.org.uk/USD-INR-exchange-rate-histo...