how will we come to know by looking at this page that there was short selling.

I don't know that you can. Short selling usually involves selling through a brokerage a stock that you don't actually own. You have to be approved for margin trading and be cautious of calls. The only thing that might indicate short selling is a higher than usual trading volume combined with a significant loss on that day. But even that is only a speculation; people may have been dumping the stock because it was simply going down in price.