First, I pasted the brown color packing tape all over the edges of the door. Then stuck thermocol over the gaps in, under and over the door and taped it again. Then made a thermocol door (pasted 4x2 thermocol pieces and taped them), stuck it, leaving 4'' gap from the closed door, between the walls where the door. So far so good. There was considerable reduction in the noise when they switched on TV some time back. It made me feel good, having done all the work for nearly three hours on my own. To make it (sound reduction) more effective, planning to buy a heavy curtain and hang it in front of the thermocol door.
As you can see it is far from a neat and professional work but has helped in improving the situation. The picture captures only the top half of the thermocol door as taking the picture of the entire door would have meant removing and rearranging all my laptop and accessory wiring. If someone who needs a solution for cutting down noise finds this article, this article would have achieve its purpose.

