The Námaste is the original greeting from India and is used both to greet and to say goodbye, as well as to thank, show respect or pray. It is accompanied by a slight tilt of the head together with the palms of the hands pressed together at the chest and more or less below the chin. It is also a very widespread gesture in yoga practices. You have all the information in: «Indian customs«.
You have all the information in: "Indian customs".