Is there a special kind of Electromagnetic Field existing in or near South West Sikkim and what are it's geographical and astrological importance for the local inhabitants?

"Electromagnetic" implies that electricity is involved somehow, and is generally man made. You may find more results searching for "magnetic" or "geomagnetic" on google or a similar search engine. There are also some good references on google earth, if you enable the community layer. This may be a starting point for your research.