I live in India and would like to know whether it is legal to listen to on the air transmissions there.
I know that transmitting is allowed only in limited frequencies and strictly require a HAM license here. But does it apply for reception also?
Two things here. Per the 1984 amendment to the Amateur Service Act vide. GSR#1225/84
IMHO this means you may not listen in. But don't take my word for it (+: phone the WPC/Amateur Section (the number is listed on the WPC website)
The Wireless Telegraph Act 1973 says: “The receiving apparatus of any wireless telegraph shall not be used for any unauthorized reception or interception of wireless telegraph communications”. I suspect this is more to do with listening in to police or aircraft radio (for which two UK plane-spotters [were] charged with intercepting communications in 2010) rather than listening to amateur transmissions.
The Act is quite similar to the UK law, which still forbids listening to unauthorized transmissions (UK guidance: Guidance on Receive-Only Radio Scanners). I suspect you'll be okay listening to amateur radio as an SWL, but I don't know for sure.
In some countries, such as England, you need a license just to use a TV, so I suppose there might be something similar in India. That said, there might also be military and government transmissions that are not legal to listen to. Sniffing cellular data or eavesdropping on cordless phones might violate privacy laws. Most laws around the world regarding what you can receive govern decrypting or descrambling a secured signal, and not reception of the signal itself. As far as amateur bands go, you can listen all you want without a license.
You might check here http://en.wikipedia.org/wiki/Amateur_radio_in_India and here http://www.hamradio.in/amateur_radio/ for more information specific to India.