::Green Giant is right.  No reason to regard a Government of India web site a reliable source for everything.  The number of public holidays in India? Sure, it probably would be a reliable source.  But length of the coastline?  I think not.  And the CIA is probably not the best either, when it comes to the precision we aspire to in Wikipedia. ) Reliability here really belongs to the academic literature of geography, oceanography and allied fields where the coastline is studied.  Their view seems to be that both estimates above are wrong:  From: "Loss of marine biodiversity - Conservation of sea turtles along the Orissa coast," by Nayak, L., Journal of Indian Ocean Studies. Vol. 13, no. 1, pp. 141-146. 2005.  "The coastline is one of the most spectacular gradients on earth since it forms the transition between the saline, aquatic environment of the ocean to the dry, air-exposed land over a distance of several metres. The total length of the world's coastline amounts to several million kilometres, India's coastline is about 8129 km and Orissa's coastline is 480 km."  Since the number seems to precise–8129 (with an "about" to boot) and not 8130–it would make it more credible.  Also, since they mention the saline-to-land transition, they are talking about the ocean-land coastline and not adding the lengths of lake shores (which in India, in any case, does not add much) or including in "coast" the extra buffer area over which the Government of India has legal (and fishing) rights.  It could be that in this paper, they are including the coastlines of the islands (which, over a hundred for the Andamans, could be substantial), while the other estimates (especially the lowest one) are for peninsular India alone.  Also, I am assuming there are some conventions about measuring at low-tide vs. high-tide, but those should be pretty well known and set by now.