Short calls and long puts are both bearish strategies. Long Put involves buying a put option for a premium. Put options give the holder a right to sell the underlying security at a predetermined price within a specified time.
In the above example, the trader can purchase a put option of HDFC Bank with a strike price of INR 1500. If the market price on expiry is INR 1470 then the trader will execute the put option and sell the shares at INR 1500 versus the market price of INR 1470. The profit potential in the long put is unlimited and the risk involved is limited to the amount of premium paid.