Authorities in south China's Guangzhou, host city of the 2010 Asian Games, Saturday said it will cancel a newly-launched free public transportation service due to the enormous public response, which might pose a security threat to the Asian Games.

The government earlier this month launched the color-coding scheme for vehicles, effectively grounding half of the city's 2.1 million private cars and those entering the city each day during the Asian Games.

As a remedy, free public transport service was to be offered for 30 working days beginning November 1.

The offer was met with unprecedented enthusiasm from Guangzhou residents. For days, subway trains were often crammed and stations were full as swarms of people lined up to take a free ride.

Now, officials with Guangzhou's transportation authorities said they had to rescind the offer as more than 8 million passengers took the subway on an average day beginning November 1, a figure "much, much higher" than the subway system was designed to carry.

Further, traffic controls were put into force 144 times during the week, which "seriously affects the normal security checks required for the Games" and causes "great inconvenience," officials said.

Guangzhou authorities plan to roll back the free-ride scheme on Nov. 8 and replace it with a cash subsidy program in which each household in Guangzhou will receive 150 yuan as a transportation subsidy from the government.

The Asian Games are scheduled to begin on November 12, featuring 11,700 athletes competing in 42 sports.