US-BOUND air freight volumes from China fell as much as 41 per cent year on after Chinese New Year as dozens of e-commerce flights were cancelled, reports London's Air Cargo News.

WorldACD data showed tonnages from China to the US dropped steeply in week 5 (27 January-2 February) and week 6 (3-9 February).

Hong Kong to US tonnages were also down 22 per cent.

"It's difficult to separate how much of that decline was simply linked to the annual holidays and factory closures in China, and how much resulted from the Trump administration's sudden decision to revoke access to Section 321 customs-free 'de minimis' import processes for imports from China," said WorldACD.

"The resulting huge customs processing backlogs led swiftly to that presidential order being suspended until adequate systems are in place to fully and expediently process and collect tariff revenue applicable, but in the meantime dozens of e-commerce-loaded freighter flights had been cancelled."

But there were similar declines in tonnages from China to Europe of -30 per cent in week 5 and a further -20 per cent in week 6, with Hong Kong to Europe tonnages holding up little better (-22 per cent, and a further -17 per cent, week on week, respectively).

However, spot rates from China to Europe were relatively stable, dipping -2 per cent in week 5 and a further -4 per cent in week 6, to US$3.91 per kilo - almost exactly their level in week 6 last year.

Spot rates from China to the US, meanwhile, dropped by -7 per cent, week on week, in week 5, and a further -3 per cent in week 6, to $3.99 a kilo, taking them -19 per cent lower year on year, with Hong Kong to US rates 14 per cent down year on year.

Air cargo tonnages to the US from other East Asian countries that celebrate LNY also declined sharply in week 5, week on week, including South Korea (-42 per cent), Taiwan (-60 per cent) and Vietnam (-58 per cent), although volumes rebounded or partially rebounded in week 6, with a +21 per cent week on week recovery in South Korea, +68 per cent rebound in Taiwan, and a +31 per cent partial bounce-back in Vietnam.