The man had already fled by the time police reached the spot.
Delhi police have filed a complaint a drunk man for allegedly setting 18 vehicles on fire in south Delhi's Madangir on Tuesday.
A video shows the man setting fire to the vehicles after opening the fuel pipe. Petrol overflowed from the tanks of six motorcycles and he set fire to each with a match. The cars parked nearby also caught fire, a senior police official said.
The police rushed to the spot after receiving information of the incident. The accused had already fled by then.
Among the burnt vehicles, eight two-wheelers and two cars were completely destroyed, while six motorcycles and two cars were burnt partially.