"Pepa" is a hornpipe which has been used during Bihu celebrations since ancient times. It was mostly blown by the Deori priests in olden times to imitate the music needed to summon Tian gods, much like the Shofar used by Jews. The Tibetans and ancient Chinese also used similar instruments named Rwa-dun for religious rituals. Later, it was used as a musical instrument for festive occasions like Bihu. An improved version of Pepa was also developed in the Chutia kingdom which was known as Kaali(made of copper) as mentioned in Deodhai Buranji(where Ahom king Suhungmung brought in Kaali instruments from Sadiya to Sibsagar).
As the buffalo population is dwindling gradually in Assam due to shrinking pastoral lands, getting a pepa is currently very difficult. Cost of a pepa in market has even reached INR2500 in recent years.