Extreme weather resulted in flight delays and cancellations at Shenzhen Bao’an International Airport on Sunday and Monday, prompting the airport to issue its first travel red alert of the year and send police equipped with riot shields in to quell disgruntled passengers.

265 flights inbound and outbound were cancelled by 8pm on Monday, while on average, 60 flights per hour were delayed. The day before, over 100 flights were delayed due to showers and thunderstorms.

By 5pm on Monday, the red alert was downgraded to an “orange alert”. The same day, the Guangdong flood control authority announced the beginning of the region’s rainy season, well in advance of the original April 15 forecast.

The delays and cancellations resulted in chaos at the airport. A number of passengers were involved in physical altercations with police, lunch boxes were strewn across the floor, and two men tried to prevent passengers from boarding a plane with rows of chairs.

Shenzhen Airport has become so notorious for delays that it was punished by the Civil Aviation Authority of China last August, forbidding the airport to take on any new flights and routes until the end of last year.

Last May, when upwards of 100 flights were delayed or cancelled, riot police were brought in to quell irate passengers that had thrown computers and food in response to the affected flights. Similar violent passenger revolts occurred in April and July 2014.

The bad weather also affected flights at Guangzhou Baiyun Airport where 75 flights were delayed for more than an hour at 10:30pm Sunday.