The total new vehicle registrations came in at 163,541, an 11.2%fall on the same period past year.
But it was sales to businesses which fell the most - 33.6 per cent - as businesses waited to see what was in store for company auto taxation in the budget, with private sales dropping just 5 per cent.
According to data published by the Society of Motor Manufacturers and Traders (SMMT), the number of new vehicle registrations fell 11.2% year-on-year to 163,541 last month, while business auto registrations fell by over 33%.
Private registrations were actually down by the smallest percentage, falling 5.1% in November.
Diesel has been particularly hit this year, with registrations declining 16.1 percent between January and November, while petrol rose 3.1 percent in the same period.
This follows the recent Budget, in which Chancellor Phillip Hammond announced he would be increasing taxes on brand new diesel cars in order to cut air pollution, rather than targeting older diesel cars, vans and trucks, that pump out far greater quantities of carbon dioxide, nitrogen oxide and other pollutants.
Fleet and overall new vehicle registrations fell for the eighth consecutive month in November as falling business and consumer confidence and concerns over future tax treatment of diesel cars hit home.
When it comes to the cars themselves, it appears the Ford Fiesta is flavour of the month, after missing out on the best-seller spot for a few months.
'Diesel remains the right choice for many drivers, not least because of its fuel economy and lower Carbon dioxide emissions.
Simon Benson, director of motoring services at AA Cars, added: "The SMMT warned last month that if the government failed to intervene, the new auto market would continue to suffer, and sadly that proves to have been the case today".
Hawes explained that the decrease in fleet registrations will have a marked impact on the UK's air quality improvements, with "detrimental environmental and economic consequences" if the market continues to shift away from the newest, cleanest diesels.