Came across a thread named Bus Ride from Cannought Place to Holland at Indiamike. Looks like it was possible to buy a ticket on such a bus in 1970s and some have tried to travel overland from Europe to India as late as 2007!
While talking to an old India hand few days ago I came across this reference about some direct bus service which use to ply, way back in 70’s from Regal cinema in Cannought Place to Holland. I am given the impression, they ply as late as 1972.
Another excellent thread at Indiamike about overland travel to India from Europe.