Twenty percent of government cars in the Guangdong provincial capital were kept off the roads and streets due to heavy smog on Tuesday, Guangzhou-based Southern Metropolis Daily reported.

It is the first time government cars were required to stay in their garages to help reduce heavy smog in the southern metropolis.

According to Guangzhou environment protection authorities, the city has been struck by heavy smog since the beginning of year.

The city’s large number of vehicles were seen as one of the culprits that caused the pollution.

Guangzhou, which has been limiting car registrations since July 2012, had 2.6 million registered cars by the end of last year.

Only 10,000 new cars are now granted monthly to locals via a lottery and public auctions.