Arctic Warbler (Phylloscopus borealis) breeds across the northern Eurasian taiga from Sweden, Finland and Norway to western Alaska. All populations migrate to Southeast Asia and the Andaman and Nicobar Islands during winter.
Just like Red-flanked Bluetail and exactly opposite to Willow Warbler and Northern Wheatear, western populations of Arctic Warbler do not migrate to Southeast Asia along the shortest diagonal route. They instead migrate eastwards to eastern Russia and China before moving southwards! An incredibly long journey and one that is repeated when they go back! This also explains why we do not see birds in passage migration through the Indian peninsula.