BEIJING- China's crude oil imports jumped 21% in March from a low base of comparison a year earlier as refiners ramped up operation amid robust fuel demand post-COVID-19, though purchases slowed ahead of the maintenance season.

The world's top crude oil buyer imported 49.66 million tonnes last month, equivalent to 11.69 million barrels per day (bpd), data from the General Administration of Customs showed on Tuesday.

March imports were down from 11.73 million bpd in February.

For the first quarter, arrivals totalled 139.23 million tonnes, or 11.29 million bpd. That compared to 10.2 million bpd over the same period a year earlier.

Refineries were maintaining high operational rates in March before the maintenance season, which typically kicks off in April.

An expanded refining capacity and a seasonal pickup in demand as infrastructure projects resumed from the winter break and farmers starting spring sowing also supported the increased crude imports.

Energy consultancy FGE estimated that refining margins at independent refineries in Shandong, the refining hub in China, rose $5.6 and $7 per barrel for gasoline and diesel cracks, respectively, in March from a month ago.

China's refined oil product exports for March rose 28.9% from February to 6.83 million tonnes, but was still down from 7.26 million tonnes a year ago.

Fuel exports in the first quarter reached 17.79 million tonnes, down 1.2% on year.

Natural gas imports, including piped and liquefied natural gas (LNG), were 8.73 million tonnes in March, up 26.1% from a year earlier.

(Reporting by Muyu Xu and Shivani Singh; Editing by Christopher Cushing and Muralikumar Anantharaman) ((muyu.xu@thomsonreuters.com; +86 10 56692117;))