This photo taken at 7:37 pm on Dec 29, 2014 shows dealers trying to get keys for new cars just sold at the door of an office at a car dealership in Shenzhen. [Photo/CFP]

Authorities in Shenzhen, one of China's most industrialized cities, announced at 5:40pm on Monday that the city would put a cap on sales of new cars with residents only permitted to acquire a new vehicle either by lottery or auction.

Starting from 6 pm Monday, only 100,000 new car plates will be allocated per year, a number which includes 20,000 electric cars.

Upon hearing the sudden announcement, local residents made good use of the window of 20 minutes to rush to dealerships to buy a car.