It does appear to be a batillarid. The taxa were recently revised, see http://onlinelibrary.wiley.com/doi/10.1111/j.1463-6409.2009.00390.x/abstract;jsessionid=7083F8ECDA8035518823B0FDB5DE7052.f01t04
There are likely several gastropod species in this photo. A possible columbellid is at top left, Thirty-one species of mangrove gastropods from Sundarbans Biosphere Reserve are reported by Dey, A. 2008. Commercial and medicinal important molluscs of Sunderbans. Rec. Zool. Surv. India Occasional Paper No. 286, pp.1-54. Another paper (http://www.ijapbc.com/files/11-3208.pdf) figures a few Sundarbans cerithids. For identification, gastropods are typically photographed in front (apertural) view with a scale for size.