Unconsumed food in an event like marriages, parties will be reported by citizens through interactive social media channels like Instagram and twitter with hashtags reporting location, avenue, and other necessary details, addressing local handles of food delivery business. (for eg @zomatoDelhi or @foodpandaMumbai) which in turn reach out to huge no of followers.
NGO's can simply follow their social media accounts for updates reg excess or unconsumed food.
To address food transportation issues, NGOs can make a deal with the same contract group which supplied Food services to the event. The borrowed things like utensils and other literary can be collected by the contractor as informed by the NGO.
This is a win-win situation for everyone , as the brands can gain loyalty by simply operating local social media handles , NGOS can seek a reliable source when they are in need, and it's easy and memorable for the users to tag "food apps" as they are already notorious.
In return, the "food apps" can offer some coupon codes to the users who contributed to saving food.