Agarbatti is lighted before the images of gods and goddesses
during Hindu Puja ad worship. It is basically lighted to purify the air and
spread fragrance. It is also believed that lighting Agarbatti helps in warding
of the evil spirits.
Basically, Agarbatti is burned to keep away bad odors which
attract evil or the demons.
It is believed that when Gods arrive to participate in the
puja, the paths through which they arrive are kept smelling sweet and fresh
with agarbattis.
What is pleasing to human beings is presumed to be pleasing
to the gods and therefore good smell of Agarbatti is used in pujas.
It is also believed that the smoke of Agarbatti is similar
to the smoke of sacrifice or yajna and therefore it is offered to please the
deities.