Nonlocal motor vehicles will be allowed to stay on Hainan Island for only a maximum of 120 days a year from mid-2019, the provincial government announced on Tuesday.

The regulation, to come into effect on Aug 1, will exclude categories including electric vehicles, special purpose vehicles, ambulances and fire trucks.

All other nonlocal vehicles planning to enter the tropical island will have to get advance permission from the provincial Traffic Department, either online or by phone.

Those found driving nonlocal vehicles in Hainan without a valid permit will be punished, the authorities said.

Every year, especially during the Spring Festival holiday, millions of vehicles from the mainland rush to Hainan, causing severe traffic jams and air pollution.

“All these measures come amid Hainan’s efforts to maintain its excellent ecological environment,” Sun He, head of the provincial Public Security Bureau’s Traffic Police Department, told a news conference in Haikou on Tuesday.

Detailed management measures for a provincial policy restricting car purchases were also released on Tuesday. The vehicle quota for the rest of this year was set at 50,000.

Locals, migrants and long-term foreign residents who have driver's licenses will be able to enter a lottery or auction for the right to purchase a gasoline-fueled car or sign up to purchase an electric vehicle.

The quota policy, effective from Wednesday and first announced in May, aims to curb the rapid increase in car numbers on the island and promote the use of new energy vehicles, the provincial government said.

The move makes Hainan the ninth region to adopt such a policy, joining Beijing, Shanghai, Tianjin, Guangzhou and Shenzhen in Guangdong province, Guiyang in Guizhou province, Hangzhou in Zhejiang province, and Shijiazhuang in Hebei province.

At a news conference on Wednesday, the Haikou city government announced that it will add 300 electric buses to its urban traffic network this year. That will take the city’s bus fleet to 2,171, with 84 percent of them electric.