BEIJING (Reuters) - Chinese export hub Guangdong has stopped publishing a monthly economic indicator that gauges growth momentum in its massive manufacturing sector after central authorities claimed local surveying and publication of the data to be “illegal”.

FILE PHOTO: A boy looks at cargo ships passing along the Pearl River in Guangzhou, Guangdong province, August 6, 2014. REUTERS/Alex Lee/File Photo

The southern province of Guangdong, famed for its vibrant tech scene and vast factory base as one of the first beneficiaries of China’s opening policy, has been particularly vulnerable to China’s bitter trade war with the United States this year as billions in U.S. tariffs hit Chinese exports.

Its manufacturing purchasing managers’ index (PMI), published monthly by the Guangdong Department of Industry and Information Technology, had been treading lower than the official index for five straight months until the data series stopped updating in October.

In a bearish sign for the industry, the value of export orders to the United States signed in November at China’s largest trade fair in Guangdong’s provincial capital Guangzhou dropped 30.3 percent on the year.

The abrupt data suspension breaks a near seven-year tradition since Guangdong started the series at the end of 2011. In its last release for September, Guangdong’s PMI was 50.2, compared to the official gauge of 50.8 for the month.

In a Q&A published on its website on Tuesday, the National Bureau of Statistics said it received complaints at the end of October that Guangdong had been illegally surveying for a monthly index.

“The investigation showed that Guangdong’s Department of Industry and Information Technology failed to renew approval from the statistics bureau after its previous registration expired,” the bureau said.

It added the Guangdong government had also been publishing the PMI data without submitting the numbers to the bureau first to be audited and approved.

The bureau said Guangdong was taking corrective measures and if conditions were met, the data release could be resumed again in the future.

The Guangdong Department of Industry and Information, in response to an anonymous inquiry on its website about the missing data on Dec. 10, said it received notice from the bureau at the end of October that surveying for the PMI index should be arranged by the bureau and the department had stopped data collection at its request.