The trade between southwest China's Tibet Autonomous Region and Nepal saw a drastic decline in the first five months this year due to a devastating earthquake in April, according to local customs on Saturday.

The trade volume between the plateau region and Nepal in the first five months reached 2.4 billion yuan (393 million U.S. dollars), down about 40 percent year on year, according to the Lhasa customs.

The import and export dropped by 47 percent and 37 percent respectively during the same period .

The customs attributed the trade decline to the earthquake on April 25, which brought Tibet's export to Nepal to a standstill in May.

Tibet's trade to Nepal could not recover to normal in a short period of time as roads in Nepal were badly damaged in the earthquake and the upcoming rainy season will make the repairs more difficult, said Li Gang, head of the customs in Nyalam, a major customs that borders Nepal.

Nepal has been Tibet's top trading partner since 2006. The trade between the two sides reached 10 billion yuan in 2014, accounting for more than 90 percent of Tibet's foreign trade.

The 7.9-magnitude earthquake which struck Nepal on April 25 and ensuing aftershocks have left nearly 9,000 people dead and destroyed or damaged tens of thousands of houses in Nepal. The death toll from the quakes stands at 25 in Tibet.