This chokes the pipes and clogs the kitchen drain. Such clogging is unhygienic and should be taken care of immediately.
Straighten a wire hanger and bend one end to form a hook. Put the hook in the sink to remove food particles and other gunk that is blocking the drain.
Add a spoon of liquid detergent to boiled water. Pour the boiling water into the drain to dissolve the sludge and fat on the walls of the drain. Repeat the process for a couple of more times to allow drain pipes to run more freely.
Take a cup full of baking soda and pour it into the drain followed by another cup full of vinegar. Let the mixture sit for 15 minutes. Then pour another bucket of boiling water for the final blow.