There’s no absolute prohibition for short selling, however, one must be mindful of the risks involved as well as any immoral implications of the assets you might be trading.

In short selling you are borrowing a stock from your broker and selling it to a buyer, hoping that you’ll be able to buy it cheaper before returning it to the broker. Essentially, you’re selling something at the market price and buying it back at a later time for a lower price.

This is no different from a shopkeeper who doesn’t own a particular color of a shirt so he borrows it from the next door shop and sells it to the customer. Then at a later time he buys the same shirt at the wholesale price and returns it to the next door shop.