Every year on February 14, the entire state of Arunachal Pradesh one of its most important festivals--Sangken. Though celebrated all over the state, it is mainly celebrated by the Khampti tribe. Lohit district, the home district of the Khamptis is where you should be during the festival. The festival marks the New Year and goes on for three days during which worshippers bathe Buddha's idol.
The festival is celebrated by the Nyishi tribe on February 28 every year. The two-day festival is a celebration of land and people. A lot of singing and dancing happens during the festival and one needs to be in East Kameng, Lower Subansiri, Kuring Kummey and Papum Pare districts.
The festival is the most important one for the Monpa tribe of Tawang and West Kameng. To experience Losar the best way possible, you need to be in Tawang in late February to early March. The festival is celebrated for around 15 days during which one can see homes fully decorated with prayer flags and butter lamps. It's a pretty sight!
It is the most important festival of the Galo tribe. The festival is celebrated during March-April and is also the New Year for the tribe. The tribe follows Donyi-Polo, an animist religion. During the festival, the Galos wear their traditional best and drink Apong, the popular local alcoholic beverage. Festival goers also apply rice flour on each other, a holy ritual for the them. Be in West and East Siang for Mopin.