ABUJA — Nigeria’s naira hit a record low at a central bank foreign exchange auction on Dec. 30, traders said, as the bank lets the local currency weaken to cope with rising dollar demand.

The central bank sold foreign currency at between 490 and 500 naira per dollar, compared to 481.50-497 naira per dollar on Dec. 16 and 465-495 naira on Nov. 4.

The auctions usually take place every two weeks, with another auction due to happen on Friday.

The central bank has allowed the naira to fall to preserve the country’s international reserves and meet rising foreign exchange demand from importers.

The bank is the main supplier of foreign exchange in Nigeria, selling dollars to airlines, and importers of raw materials, petroleum and agricultural products directly, and intervening on the spot market.

The naira traded between 460 and 462 naira per dollar on the spot market on Friday, a record low range struck in December after the central bank adjusted the rate.

The currency has dropped to 747 naira per dollar on the black market where it trades freely, as business activity has picked up after the holiday season.

International financial institutions like the World Bank have called on Nigeria to merge its multiple exchange rates.

Nigerian President Muhammadu Buhari has sought to keep the naira strong as a matter of national pride, but that became unsustainable during an oil price crash in 2016. To avoid a large devaluation, multiple exchange rates were introduced. (Reporting by Chijioke Ohuocha Editing by Alexander Winning, Sharon Singleton)