Well, AFAIK, they will allow connections as long as there is a 2 hour gap (shorter for some airlines like LH). What they don't factor in when they do that, is that a case like yours is not just an international transit, it is in a place like DEL, for Heaven's sake ! That means that unless you're flying J or F (and therefore are either first up or use fast-track immigration), you must prepare for enough people jumping the queue, throwing their weight around for faster processing, etc. Sad but true. Let me know if any of that DOESN'T happen and your immigration processing is uneventful !