Bhairab is one of Lord Shiva’s manifestations or another form of Shiva. Lord, Shiva is regarded as guardian of mankind; however, his another form is Bahirav, angry form of Shiva. Bhairav is regarded as destructive incarnation of Shiva.
Pachali Bairav is in Pachali, a place in Tekhu(teku) Kathmandu.
The worship and procession with a big feast is called Jatra, mainly in Newari culture.
Therefore, Pachali Bhairav jatra is worship and procession of Lord Bhairav situated in Pachali with a big celebration and feast.
The Lakhey Band (First Newari Metal Band ) Video footage of Pachali bhairav Jatra.