Reasons of discount on fruits and vegetables in supermarkets ?

Shopping malls, departmental stores, fresh houses generally give the discount on the certain product on particular seasons/month/day.

What are the reasons behind it? What are advantages and disadvantages of these discounts?

Discounts may be offered for various reasons. Whatever reasons may be, but ultimately discounts are offered to increase the sales. Sometimes discounts are offered to finish the remaining perishable stock or stock of near expiry date.

In Shopping malls/departmental stores/fresh houses, they generally purchase vegetables and fruits once a week on a particular day and makes sales throughout the week. For vegetables and fruits items discounts are offered on the certain day of the week, generally, before the day fresh vegetables and fruits are bought. Therefore by offering the discount on vegetables and fruits that are about to expire are sold.

Therefore sellers get benefited by selling their vegetables and fruits that was about to expire/perish.

Therefore as a consumer one should be aware that, there is the reason for offering discounts on vegetables and fruits. And be sure that you compare the freshness of the vegetables and fruits with the price quoted for it. And be sure that you aren't going to purchase vegetables and fruits that are about to rot just for the discounts.