HANOI, Aug. 11 (Xinhua) -- Up to 60-70 percent of air pollutants in Vietnamese big cities such as Hanoi and Ho Chi Minh City stem from transport activities, said a leader of the Vietnam Environment Administration.

To minimize air pollution, Vietnam should further develop public transport, and apply new stricter international criteria for vehicles' emissions like Euro 4 standard, local daily newspaper Tien Phong (Pioneer) on Friday quoted Hoang Duong Tung, deputy head of the Vietnam Environment Administration under the Ministry of Natural Resources and Environment, as saying.

According to Vietnam's latest regulations on vehicles' emissions, diesel-powered automobiles will have to meet Euro 4 standard from Jan. 2018.

Euro 4 standard has already been applied to petrol or gas-powered automobiles in Vietnam since January 2017.

Vietnam is making infrastructure and trading preparations for ensuring sufficient supply of diesel which is in line with Euro 4 standard, according to the country's Ministry of Industry and Trade.

Vietnam's two biggest oil refineries, Dung Quat and Nghi Son, should produce more products which are in line with Euro 4 standard, local experts said, noting that their current outputs cannot meet the domestic demand, so the country will have to import certain amounts of such kinds of fuels.