Dear Deepali,
By nature, when any function comes, we normally plan to give sweets, coffee cups, or chocolates to relatives or friends. We give crackers or diaries for our clients, and we give cash vouchers, Sodexos, bags, or watches to employees. This is a tradition that most people usually follow.
Being more interested in nature, I would like to suggest why not give a sapling (small plant) to all of them and ask them to plant it in their home or a small tree they can plant in some space on this earth. One day, if you go to their house, they can show you how much it has grown, and this can also help build your relationship with them.
Alternatively, you can have a book made of recycled paper (Neenah paper) with excellent quality containing some articles about health tips or something that spreads awareness about the environment.
Please think about this and let me know if you are interested. My email address is: [Login to view].
Regards,
Goutham :-)