Hey Shobhit: Prices of almost all lenses have increased.
Most of the camera manufacturers have their manufacturing units (Lens/Cameras/parts) in Thailand in order to serve the sub-continent where price sensitivity is very high. Because of the recent flood situation there, most of these factories are closed and some are running short on their number of units.
As a result of this situation, these lenses are being imported from other manufacturing units based in Europe/US or wherever. As a result of this there has been an increase of prices of these electonic items.