A Chinese airline has been stripped of routes and given a large fine after some of its pilots turned back flights amid suspected industrial unrest.

China Eastern Airlines was punished by the country’s civil aviation authority after the incidents earlier this month.

The carrier had claimed that the flights had returned to Kunming airport after take-off due to bad weather but later admitted a “human element”.

Pilots had been demanding better pay, hours and working conditions.

Protest rare

Fining China Eastern 1.5 million yuan ($215,000; £108,000) and giving some of its routes within Yunnan province to rival airlines, the carrier was told to punish those responsible and uphold safety.

State media reports suggested that 21 flights coming out of the south western city of Kunming had reversed course.

There have been separate claims that other pilots co-ordinated “sick days” – with about 40 Shanghai Airlines crew not coming to work on one day last month.

They were reportedly angry over deals tying them to their employer.

Pilots have been told to sign 99-year deals with state-owned airlines which force them to pay up to 2.1 million yuan ($300,000; £150,000) if they quit, China Radio International said.

The contracts are thought to be aimed at stopping the poaching of pilots by rival carriers.

Industrial action is rare in China – where unauthorised protests are banned.