The basic source of records for Europeans in India (including Anglo-Indians) are the baptism, burial and marriage registers in the India Office Records held at the British Library. Many of these have been transcribed and indexed by the LDS and can be found on the FamilySearch site https://www.familysearch.org/
- however this is not a complete set. Also try the Families in British India Society which holds diverse transcribed records http://www.fibis.org
. The BL also have their own searchable site which draws records from their great card index: http://indiafamily.bl.uk/UI/
. I regret that my searches in these on-line data bases have not identified Sona Ward or her father Robert Charles Ward. Do you have any more information about the family?
I understand that FindMyPast have a contract with the BL to index and upload images from the India Office Collection, the 'complete' Church Records are expected to be available soon. When doing your India searches, you also need to be aware that in fact the Church records at the BL are not actually complete, as not all churches sent copies of their records back to the India Office - if your family were R.C., Presbyterian or some other non-conformist (particularly if they belonged to an American or other foreign missionary church, then you may not find any record in the BL collection.
Do make good use of the FIBIS site, particularly the FIBIwiki where you will find plenty of advice and background information.
Good hunting! Sylvia