If you are searching for ancestors who lived in British India, you may find some of their birth, marriage and death records at FamilySearch. Put the family surname, and India under country name at the top of the search engine, and you may well find useful resources. You also may find it useful to do a 'parent search', which will bring up the names of all children born to a particular couple (at least the ones whose records were listed) as well as marriages of those children. In this case, you simply put in the parental surname at the top and then the names of the parents at the bottom of the search engine (you can put in a country name i.e India, but you also can leave country name blank, which may bring up references to a couple in another country - if they returned to the UK, for example).
Other useful resources include FIBIS, the Families in British India Society, and the India Office records of the British Library
Other useful resources include FIBIS, the Families in British India Society, and the India Office records of the British Library