BEIJING: China's notoriously smog-bound capital Beijing asked residents on Friday to set off fewer fireworks over this month's Chinese New Year period as it battles a persistent air quality crisis.

Air quality in Beijing has mostly stayed above "very unhealthy" and "hazardous" levels for about two weeks, though strong winds cleared the haze away on Friday.

Chinese New Year, which begins Feb. 10, is marked by riotous fireworks displays traditionally thought to bring good luck for the year ahead, which turn cities into near war zones and blacken the skies with thick smoke for hours on end.

"To improve the air quality and create a favourable environment for you and your family members, please set off fewer fireworks or no fireworks, in order to reduce emissions of pollutants," the official Xinhua news agency cited an unnamed official with the Beijing Office of Fireworks and Firecrackers as saying.

The city's three main fireworks retailers have reduced to 750,000 the number of cartons of fireworks in stock for this year's festivities, down from 810,000 last year.

The number of shops approved to sell fireworks in has also been cut to 1,337 from 1,429, Xinhua added.

Pollution in Beijing regularly exceeds 500 on an index that measures particulate matter in the air with a diameter of 2.5 micrometers. Above 300 is considered hazardous, while the World Health Organisation recommends a daily level of no more than 20.

Last month pollution hit a record, 30-45 times above recommended safety levels, blanketing the city in a thick, noxious cloud that grounded flights and forced people indoors, and prompting emergency measures such as factory closures.