This is a female. Males are blue above. This species is split from the Red-flanked Bluetail (Tarsiger cyanurus) by Clements, IOC and H&M (Rasmussen & Anderton 2005, Luo et al 2014) but not yet by HBW or OBC. The differences are most pronounced in the males but female Himalayan Bluetail are longer tailed and somewhat grayer on chest and brighter blue on the tail as seen here. Note also trace of pale supercilium. This species is usually considered monotypic but Rasmussen recognizes the race T. r. pallidor from the NW part of its range and averaging paler than populations further east. Sometimes called Himalayan Red-flanked Bush-Robin or Orange-flanked Bush-Robin. These birds in the subfamily Saxicolinae (Old World Chats) were formerly classified as members of the Thrush family (Turdidae), but as first proposed by Sibley and Monroe are now usually recognized as members of the Old World Flycatchers (Muscicapidae). The generic name Tarsiger means "flat-footed." Canon PowerShot SX50 HS.
References:
Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2016. The eBird/Clements checklist of birds of the world: v2016. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
Collar, N. & de Juana, E. (2016). Orange-flanked Bush-robin (Tarsiger cyanurus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/58468 on 19 September 2016).
Dickinson, EC & L Christidis (Eds). 2014. The Howard & Moore Complete Checklist of the Birds of the World. 4th Edition. Vol. 2 Passerines, Aves Press, Eastbourne, U.K.
Gill, F and D Donsker (Eds). 2016. IOC World Bird List (v 6.3). http://www.worldbirdnames.org/
Luo S, Wu Y, Chang Q, Liu Y, Yang X, Zhang Z, Zhang M, Zhang Q, Zou F. (2014) Deep phylogeographic divergence of a migratory passerine in Sino-Himalayan and Siberian forests: The Red-flanked Bluetail (Tarsiger cyanurus) complex. Ecol Evol. 4:977-986.
Rasmussen, P.C. & Anderton, J.C. (2012) Birds of South Asia. The Ripley Guide. Vols. 1 and 2. Second Edition. Smithsonian Institution. Michigan State University & Lynx Edicions, Washington. D.C., Michigan & Barcelona.