BEIJING — Chinese authorities say four people have been killed and five injured in an explosion at a stall selling fireworks on the eve of the Lunar New Year holiday.

The information office in Tonghai county in the southwestern province of Yunnan says the blast occurred at around 11 p.m. Thursday. It says the cause of the explosion is under investigation.

Friday marked the start of China's most important traditional holiday, with tens of millions traveling across the vast nations for family reunions.

Fireworks have generally been a major part of the festivities, although authorities have cracked down on the practice for safety reasons and to cut down on air pollution.

Cities such as Beijing and Shanghai that used to shake from fireworks have been eerily quiet this year.