Mr Kumars point is well taken. But what the article's suggesting is that there were more invasions by foreigners from the lands to the west of India, beyond the Brit-established frontiers of the Khyber and Bolan Passes, into India than the other way around.
Few if any marches from the east other than those under the Brits went beyond these Passes. The Brits didn't fare too well in the first two Afghan Wars. They maintained a tenuous peace on the frontier at considerable cost in blood and treasure.
