There are plenty of possibilities from WAS to DEL. Some of your possible connections excluding Europe as you stated:
IAD-EWR-DEL (CO)
IAD-ORD-DEL (AA)
IAD-JFK-DEL (UA/AI)
IAD-DOH-DEL (QR)
IAD-DXB-DEL (UA/9W or UA/AI)
IAD-KWI-DEL (UA/KU)
If you want to take a stop in Europe - you almost have an infinite supply of choices via LHR, CDG, AMS, BRU, FRA, MUC, VIE, ZRH etc.