The number of passengers who violated rules of inflight conduct more than doubled in 2014 from a year earlier, mostly led by smoking in the cabin, industry data showed Sunday.

Korean Air Line Co., South Korea’s largest full-service carrier, last year reported 246 cases of unruly behavior, including smoking, air rage and sexual harassment, compared with 120 in 2013.

Smoking, punishable by fines up to 1 million won ($916.5), soared to 190 cases last year from 90 a year earlier.

Among 490 passengers who violated aviation safety rules over the past three years, Korean Air handed over 155 to police, with 39 becoming subjects of legal punishment.

No. 2 Asiana Airlines Inc. reported 51 cases of unruly passenger problems from January to November, more than triple the figure recorded the previous year, with smoking accounting for the highest ratio of violations.

According to the Ministry of Land, Infrastructure and Transportation, the number of safety violations by air passengers rose to 187 in 2013, up from 140 in 2010. A total of 190 cases took place in the first seven months of last year.

Among 843 cases over the past five years, 81 percent were related to smoking and commotion accounted for 12 percent, followed by physical abuse and sexual harassment with 5 percent and 2 percent, respectively, the ministry said.

Unruly behavior of passengers has become a growing concern among local airlines, raising calls for clear regulations to prevent such behavior.

On Wednesday, Bobby Kim, a popular R&B singer in South Korea, was questioned by the U.S. investigators after his alleged sexual harassment of a cabin crew member while intoxicated on a Korean Air flight from Incheon to San Francisco.

Korean Air found itself in hot water after its former vice president and the eldest daughter of CEO Cho Yang-ho sparked national uproar after ordering a crewmember to deplane over in-flight service last month.

Cho Hyun-ah was indicted Wednesday on charges of obstructing aviation safety after ordering a chief flight attendant to deplane over the way she was served macadamia nuts, in an unopened pack instead of on a plate. (Yonhap)