Delhi is 3.5 hours ahead of Brussels

Best overlap: 8:30 AM to 2:30 PM in Brussels is 12:00 PM to 6:00 PM in Delhi.

For the smoothest call, aim inside 8:30 AM to 2:30 PM in Brussels, i.e. 12:00 PM to 6:00 PM in Delhi. That's a roomy 6 hours of common time each day, so finding a slot that suits everyone is rarely a problem. Note that Brussels follows daylight saving while Delhi stays put, so the times above drift by an hour seasonally.