TIANJIN, June 11 (Xinhua) -- Total imports and exports by customs special supervision areas in north China's Tianjin Municipality reached 55.86 billion yuan (about 7.89 billion U.S. dollars) from January to April this year, local authorities said Wednesday.

The foreign trade by Tianjin customs special supervision areas accounted for 26 percent of the city's total foreign trade during the period, according to Tianjin Customs.

Since 1991, Tianjin has established five customs special supervision areas including several comprehensive bonded zones to facilitate cross-border trade and economic development. They cover a total area of around 18 square km, about 0.15 percent of the port city's land area.

The areas include industrial clusters including aviation manufacturing and maintenance, international financial leasing of aircraft, ships and marine equipment, cross-border e-commerce, and bonded warehousing of bulk commodities.

As important platforms for an open economy, the areas have taken advantage of special location and favorable policies to develop foreign trade, attract foreign investment, and promote industrial transformation and upgrade, said Huang Chunyan, deputy director of the Tianjin Commission of Commerce.

In 2019, imports and exports by Tianjin customs special supervision areas reached 199.8 billion yuan, accounting for 27.2 percent of the city's total foreign trade.