That, dear Abhisek, is the mystery of success. Cable screen and signal ground may only be connected together at certain, well defined points. Never take the shield as simple ground connection and vice versa. Every signal must have it's ground return line running as close as possible to it. That minimizes current loop. But cable shield must surround signal and ground return line completely, forming a completely surrounding Faraday cage. Only where a cable goes into an enclosure or leaves it, signal ground must be connected to Faraday cage (enclosure). And from inside. Either directly (hard grounding) or via 10nF (soft grounding).
When at cable entry or exit of enclosure some filtering is neccessary, filter ground has to be connected to Faraday cage, at the same point, where signal ground is connected to Faraday cage and both directly at cable entry point.
There's only one solution still better than this scenario: Use of symmetrical signal.

Bye,
Kai