Beijing [China], July 13: A state-owned Chinese airline, Air China, the flight had to descend on Tuesday after a co-pilot smoked an electronic cigarette mid-air.

The South China Morning Post quoted an official statement of the Air China which was issued on the micro-blogging site Weibo. The statement said: "If the investigation reveals that the crew has violated regulations, the company will seriously deal with the responsible person with zero tolerance".

The incident happened on the night of July 10. And, the result of the preliminary investigation came out on July 12. The South China Morning Post reported that the Dalian-bound flight from Hong Kong suddenly descended to 25,000 feet from 35,000 feet.

The People's Daily, the media mouthpiece of the Communist Party of China in their official twitter handle said that, the aviation authority in their initial investigation found that the sudden dropping was a result when a co-pilot smoked an electronic cigarette during the flight and mistakenly shut off the air-conditioner trying to prevent the smoke from spreading in the cabin. The cabin made an announcement saying that the aircraft was carrying out an emergency descent due to cabin decompression.