China’s oil reserves have reached nearly 100 days worth of imports, and finding additional storage tanks and facilities has become increasingly challenging, said two people with knowledge of supply levels.

Beijing followed a push from Beijing to buy unrefined purchases for its reserves after prices crashed last year due to the coronavirus pandemic. The figure presents official and commercial lists, who said people could not be identified because they did not have their information. In one person, stocks fluctuated but the price was consistently above or above 100 days of imports and has recently risen to 120 days, one person said.

As Bloomberg reported in April last year, Beijing has set a target of increasing government reserves to at least 90 days of net imports. This goal did not include commercial content. China’s National Energy Administration did not respond to a request for comment.

As the world’s largest oil importer, adequate level reserves are important for economic resilience to supply shocks like the war in the Middle East. The International Energy Agency, which does not belong to China, recommends that countries have a sufficient unpaid amount of net imports of at least 90 days.

“In terms of crude stocks, we believe that China’s target will not stop at 100 or 120-day stocks,” said Mia Zheng, an analyst at industry consultancy FGE. “National security is one of the priorities for years to come and it will continue to maintain stock builds.”

Unlike the United States, where information on the country’s strategic petroleum reserves is made public and regularly updated, the size of China’s crude reserves is shrouded in mystery. There is also little difference between government reserves and commercial stock styles, with most of the country’s largest power companies state-owned.

China was moving ahead with plans to buy oil for its emergency deposits in April last year, people familiar with the plans said at the time. The initial target was to keep government stock styles equivalent to 90 days of net imports, which could eventually be extended to 180 days after being included in the archives commercially, they said.

Last year’s oil price crash and China’s rapid return from the first wave of the Covid-1p epidemic set the stage for the opening of crude purchases. However, the stock price has remained flat as oil prices have returned and storage space has run out, Capital Economics Limited said in a note this month. Fuel demand has also declined this year amid coronavirus resurgence in some parts of China.