FILE PHOTO - Traffic congestion is pictured in Shanghai, China, April 19, 2017. REUTERS/Joe White

SHANGHAI (Reuters) - China is considering testing a ban on gasoline-powered vehicles in some parts of the country and may set a timetable to eventually phase out such vehicles, according to the industry ministry.

The government has encouraged sales of electric vehicles as part of a crackdown on pollution, but auto industry officials doubt it will completely phase out traditional internal combustion engines given regional differences in climate and environment.

Authorities must first analyze factors such as market demand and emission levels to decide whether to test no-go zones for gasoline-fueled vehicles, according to a document on the Ministry of Industry and Information Technology (MIIT) website.

The document was issued in response to a proposal from China’s parliament on July 16 and reported by Chinese state media on Wednesday.

China is the world’s largest NEV market, with 1.3 million units sold last year. NEV sales, which include battery electric and plug-in hybrid vehicles, are expected to reach 1.5 million units next year.

The ministry may formulate a timetable to phase out gasoline-fueled vehicles, according to the document, but did not say if it would be specific to certain parts of the country or a nationwide phase out.

China’s southern province of Hainan, said in March it plans to stop selling gasoline vehicles by 2030.