As Keyser Said, Customs has a list a TV models and Price in india - Based on which you have to pay tax.

Second hand experience, flying from SIN with a friend/colleague , he brought a 32" LCD (350 SGD) - the Price in india was about 23-24K INR and customs let him go without any tax / duty / bribe. Another guy in same flight, had a 40" LED - though the price was about 450 SGD, he has to pay the tax on indian price which was around 70K INR even though he had the invoice / CC charge slip etc for 450 SGDs.

If you happen to fly from SIN, you would be amused by the number of LCD TVs they load to each flight to india - I had seen 2 Luggage carts full of them (Around 40 LCD/LEDs) around last Diwali.

Also there are enterprising folks in Singapore, who come to SIN airport every day with 5-10 sets and solicit volunteers who can take a TV set to india for some gift in return.