tempest in a teacup/ teapot
The congestion is because of a surge in oil imports from a group of privately owned refiners—dubbed “teapots” because of their small size compared with giant state-owned companies, such as China Petroleum & Chemical Corp., or Sinopec, PetroChina Co., and China National Offshore Oil Corp.—that is shaking up China’s oil industry and stoking global markets.
storm in a teacup
Also, tempest in a teacup. A great disturbance or uproar over a matter of little or no importance. For example, All that because a handful of the thousand invited guests didn't show up? What a tempest in a teapot! This expression has appeared in slightly different forms for more than 300 years. Among the variations are storm in a cream bowl, tempest in a glass of water, and storm in a hand-wash basin. The British prefer storm in a teacup. The current American forms were first recorded in 1854. For a synonym, see much ado about nothing.