China is suspending local meteorological bureaus from issuing smog alerts, media reported Wednesday, raising suspicions the government is attempting to suppress information about the country's air pollution as public anger over the issue grows.

China's Meteorological Administration notified local bureaus Tuesday to "immediately stop issuing smog alerts", according to a photo of a notice posted on China's Twitter-like social media platform Weibo.

Instead, the local departments can issue alerts for "fog" when visibility is less than 10 km, according to the notice.

The notice was issued because local "meterological bureaus and the environmental protection administration often disagree when they issue smog-related information," a representative from the China Meteorological Administration told the Chinese website The Paper.

"A joint alerting mechanism will be formulated to consult how to and who should issue alerts for smog," the representative said.

One single department will now be responsible for issuing smog alerts, The Paper reported.

The reports met with stinging criticism from online commentators who have long doubted the credibility of official data on air pollution.

"Before, they cheated us separately, and now, they are going to cheat us together," one person said on Weibo.

"Even though they are working on a unified alert standard, they should not stop the existing alert system," another replied.

The Chinese government has a colour-coded system of smog alerts, topping out at red when severe pollution is likely to last more than 72 hours.

The notice sets off a series of emergency measures, ranging from taking cars off the road to closing heavily polluting factories.

Local authorities have long hesitated to issue the notices over fears that they will harm economic performance, even when pollution levels are literally off the charts.

In late 2015, China issued its first ever red alert in response to public anger over the government's reluctance to take action after a wave of suffocating smog hit the country's northeast.

In the past, local and national authorities have issued contradictory, confusing alerts, one ordering factories and schools to be closed and one not.

Bad air is a source of enduring public anger in China, which has seen fast economic growth in recent decades but at the cost of widespread environmental problems.

In recent weeks, parents in particular have expressed outrage over the miasma that regularly affect hundreds of millions and has led to high levels of lung cancer, demanding that schools be equipped with air purifiers.

Earlier this month, many took to social media to express their anger about the thick smog that choked Beijing for over a week around the New Year but found their articles quickly deleted, a move that only increased their frustration.

"When people are gagged, the sky will be blue," said one sarcasm-laced Weibo comment.