China has suspended the release of output data for several key commodities amid a crackdown on the illegal sale of state statistics by government officials, raising further concerns about transparency in the world's second-largest economy.
With Chinese economic growth at a 25-year low, the lack of such data makes it increasingly difficult for economists to gauge the strength of local demand as Beijing tries to avert a faster slowdown.
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Key monthly output numbers for several oil and metal products over the first quarter have still not been published, and the National Bureau of Statistics (NBS) has also failed to release regional data for products like coal, steel and electricity since the turn of the year.
Officially, the NBS only releases a few key commodities statistics through its website, though more detailed numbers have been made available through unofficial channels, including third-party distributors and industry consultancies.
Most of those numbers have now dried up after China's corruption watchdog, the Central Commission of Discipline Inspection (CCDI), launched a probe into "disciplinary violations" at the NBS last October.
The bureau head, Wang Baoan, was removed from his post in late February after being put under formal investigation.
CCDI said last week that hundreds of staff working for the statistics bureau had been using official data for personal gain.
It said "individuals were not permitted to receive any royalties, editorial fees or labour fees" for the publication of NBS data, and 313 officials were now in the process of being indicted.
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"Since the inspection team moved in to the statistical bureau, there were apparently some investigations into the various ways key economic data was distributed," said a researcher with a state-backed industry association.
"We are not getting them either," said the researcher, who did not want to be named.
Production numbers for gasoline, diesel and kerosene for the first three months of the year have now been released after long delays.
But other figures, including data supplied by the bureau to third-party agencies has not been made available since November 2015. The data still missing includes monthly production figures for base metals as well as oil products like liquefied petroleum gas, naphtha and fuel oil.
"It is crucial to help gauge oil demand from China, and this lack of transparency makes it harder to gauge the strength of the demand side," said Miswin Mahesh, analyst with Barclays Capital.
"It would mean that import data and ship tracking will have to pay a larger role, although it would still not be able to give a good estimate for local demand, given China is now also a net exporter of refined products," he added.
An official at the NBS said the data releases had been "temporarily suspended", adding that it was likely that the amount of data made available to the public would be restricted.
Other missing numbers include provincial breakdowns for steel production and power generation. The suspension has affected news agencies such as Reuters as well as Chinese consultancies such as Mysteel, Antaike and ICIS, and industry bodies like the China Petroleum and Chemical Industry Federation.