Use society. I would contact the american society of plastic surgeons at http://www.Plasticsurgery.Org/ for a list of international members.
Board certified. Check the plasticsurgery.Org website to determine if there are plastic surgeons in delhi who are certified by the american board of plastic surgery.
Double chin. Need a board certified plastic surgeon, i think there are several in india.
Board Certification. Seek consultation with board certified plastic surgeons in india. Ask to see lots of examples of his/her work and preferably speak to patients who had similar surgery performed. Make sure you are a good candidate; for example, make sure that the overlying skin elasticity is such that the skin will “bounce back” nicely after liposuction surgery. Best wishes.