For this case you would use either a Strict Payment Receive or Strict Payment Send operation. But before you are able to execute that you need to find a Path Payment.
You would ask Horizon to find a Path Payment from INR to USD and you would the parameters to restrict that search. This will give you the best paths from INR to USD (in terms of exchange rate) that matches the criteria you asked.
By using the search criteria you can basically apply limits on the exchange rate.
If there are not outstanding offers that make a path from INR to USD that match your criteria, the result will be empty. Thus you know you cannot make path payment operation successfully.
When you make a path payment operation you have to give it a path, thus you need to know that it was possible at the time you issued it. But this doesn't mean that between your query time and the execution time of the transaction the conditions remain the same. If they change and now the path is not available anymore (someone else took the offer) the transaction will fail.
