Forex — Foreign Exchange charges high

In thiruchirapalli Airport, the money exchanger which is located after security check is seen charging way high than the regular market exchange rate. we had paid 18.45 INR to get 1 MYR where the market rate was just 13.75 INR.. Would like to know whether there is any regulation to set the upper limit of exchange. This will surely hamper the image of country among foreign nationals and will strongly support their belief about India as a country where you are cheated easily. Most of the money exchangers in abroad at max charged 15 INR.. Government should have a regulatory norm for these transactions.