The BLDG Blog pointed out a Google Maplet made by Carlos Labs which allows you to check out the effects of a nuclear explosion anywhere in the world.
Here's what we can expect if the Chinese launch an attack on Mumbai.
The map gives only a general picture of what the effects will be like. It does not take factors like prevailing winds and the topography into account. For example, in the example of Mumbai, daytime winds normally move from the west towards the east which would spread the radiation cloud inland.
Even so, this is an informative site and helps spread awareness of the realities of nuclear warfare.