A man buys fireworks at a certifi ed store in Beijing in preparation for the upcoming Spring Festival. Sales of fireworks started on Tuesday at 1,337 certifi ed stores across the city. [CAO BOYUAN / FOR CHINA DAILY]

Beijing weather authorities issued a firework index for the first time on Tuesday to ensure safety and reduce pollution, as sales of fireworks for Spring Festival started at 1,337 certified stores citywide.

The index, which includes three grades, gives suggestions whether conditions outdoors are suitable for fireworks.

The public can check the index by calling a hotline run by the capital's meteorological department or reading its micro blog.

The Beijing Meteorological Bureau issued a "Grade 1" firework index on Tuesday, which means the weather conditions are suitable for setting off fireworks

The index will be released every day throughout the Lunar New Year holiday, according to the bureau.

Spring Festival is traditionally the most important festival in China and is the peak season for fireworks sales.

The index is based on a variety of weather conditions, including wind speed, humidity and precipitation, and is designed to ensure safety and reduce pollution caused by fireworks, said Ding Deping, an official at Beijing Metrological Bureau.

"Setting off fireworks or firecrackers will not be safe when there are strong winds or low humidity, because it can easily cause a fire," he told Beijing Times. "But when there is no wind at all, setting off fireworks is not appropriate either, as the pollutants released will not be dispersed quickly and can worsen smog."

In January, Beijing was hit by the worst hazy weather in decades. The city had only five smog-free days last month.

The prolonged haze has alerted the public, and many urged the government to limit or even ban setting off fireworks on hazy days.