Chinese authorities have told pilots who fly to Beijing they must be qualified to land their aircraft in the low visibility bought about by smog, as the government tries to reduce flight delays due to pollution.

China's civil aviation authority says starting next year, pilots flying from the country's 10 busiest airports into the Chinese capital must be qualified to use an instrument landing system on days when smog reduces visibility to around 400 metres, according to the official newspaper China Daily.

"It is part of a series of measures the administration took recently to raise the flights' on-time performance," the newspaper quoted an unnamed aviation official as saying.

Despite investing billions of dollars in new airports and advanced Western-built aircraft, China suffers a chronic problem with flight delays.

It is partly because of the country's often wildly-fluctuating weather and partly due to the military's tightly controls over most of China's airspace.

Chinese media frequently reports fights, attacks on airport and airline workers and passengers storming aircraft in response to delays and the poor way they are handled.

The government has demanded airlines and airports address the issue.

In recent years, smog has added to the problem of delays, especially in Beijing but also in other parts of the country such as Shanghai.

"Considering the recent smog and haze has bought numerous troubles to air transport in eastern and southern regions, it seems necessary for authorities to ask pilots to improve their landing capability in low visibility," Ouyang Jie, a professor at Civil Aviation University of China was quoted as saying in the China Daily.

Only a handful of Chinese airports have the instrument landing systems required for aircraft to land in poor visibility.

Air quality in cities is of increasing concern to China's leaders after a growth-at-all-costs economic model has poisoned much of the country's environment.

China's state media came under fire earlier this week for arguing that smog had a benefit.

Reuters