Thanks Volker for your suggestion.
I tried it with my 'windows-1252' collation DB.
I did following things:
1. Converted the column data type from 'long varchar' to 'long nvarchar' to hold Non-English characters.
2. Used e.g. CSCONVERT( mytext, 'cp936' ) in FOR XML EXPLICIT Query
Although it didn't through the 'control character' error but the output was also not the actual data I have in DB.
e.g. I converted 'Sydney' to Chinese Simplified '悉尼' which saves perfectly in DB
But the output I got in the XML is "z6TE4Q==" which is not I need.
I will continue my research and request you to share your thoughts.
Regards
Ramendra