Delhi Metro Rail Corporation [Dmrc] — Eating in stations

Address:

New Delhi, New Delhi, Delhi

I am curious from when did eating is prohibited in Delhi metro stations amidst there being so many kiosk selling that.
Today while security check, guard stopped me from entering the station while eating ice cream, I asked what happened sir. He just spoke so rudely and their group just drageed me after pointing to his rude behaviour.
Later they fined me instead of telling the security officer his rudeness.
I am just confused whether I am wrong or the security personnels are free to behave in how so ever manner with the civilians.