I do this every month with all my sinks to deodorize them and unclog anything that might be stuck in the drain.
One of the most well known natural drain cleaners is a baking soda and vinegar combination. First, pour a half cup of baking soda into the sink drain. Then follow up with a half cup of white vinegar. T place the drain back over after adding vinegar and baking soda for a few minutes . Combining baking soda and vinegar is powerful enough that it can dissolve through hair, grease, and small clumps of food that may be blocking the drain. After pouring the vinegar, give an extra boost by pouring a few cups of boiling water to flush out any of the debris that was loosened after waiting the few minutes. If the drain is being particularly stubborn, it will also help to heat up the vinegar before adding it to the drain.