Vastu means the dwelling of humans and Gods. Vastushastra is an ancient science which helps one get the benefits freely offered by the basic elements of the universe.
These basic elements are Akash (SKY), Prithvi (EARTH), Paani (WATER), Agni (FIRE), and Vayu (WIND).
Vaastu Shanti worship is originally a worship of lord and deity of directions, five elements of nature as well as natural forces and other related stuffs. We perform Vaastu Shanti (worship of deity and lord of nature and their elements and natural forces as well as lord and deity of directions and environment) to remove any type of Vaastudosha whether it's a land and building, nature or environment, by Vaastushastra worship to avoid major changes and demolition in the structure of building.