Dusty weather was reported on Dec.19 in the capital of southwest China's Tibet Autonomous Region, disrupting flights and stranding more than 1,300 passengers.Four domestic and international flights were canceled due to poor visibility and 18 other flights were delayed in Lhasa's Gonggar Airport, according to civil aviation authorities.

Packed Gonggar Airport due to flight delay and cancellation on Dec.19. [Photo/Chinanews]

There has been criticism in the wake of the event. Some nitizens even claimed that "smoggy weather has finally invaded into China's last pure land." Well, it is not the fact.

Yet documents show that the floating dust weather first appeared in Lhasa in mid January, 2007 and lasted three days when most of China’s cities back then had not been affected by the haze.

According to researchers, Lhasa is an area of low convergence, with stable atmosphere and slow or static wind. It is also influenced by the upper jet stream due to large temperature gradient made by the warm and cold air confrontation. Therefore, once the gale comes, it brings tiny particles in the dry and loose land into the air and forms sandstorms. That is how the floating dust weather comes of.